GB2570765A - Resonator apparatus and method of use thereof - Google Patents
Resonator apparatus and method of use thereof Download PDFInfo
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- GB2570765A GB2570765A GB1819516.4A GB201819516A GB2570765A GB 2570765 A GB2570765 A GB 2570765A GB 201819516 A GB201819516 A GB 201819516A GB 2570765 A GB2570765 A GB 2570765A
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- cavity
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01P—WAVEGUIDES; RESONATORS, LINES, OR OTHER DEVICES OF THE WAVEGUIDE TYPE
- H01P7/00—Resonators of the waveguide type
- H01P7/10—Dielectric resonators
- H01P7/105—Multimode resonators
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01P—WAVEGUIDES; RESONATORS, LINES, OR OTHER DEVICES OF THE WAVEGUIDE TYPE
- H01P1/00—Auxiliary devices
- H01P1/20—Frequency-selective devices, e.g. filters
- H01P1/207—Hollow waveguide filters
- H01P1/208—Cascaded cavities; Cascaded resonators inside a hollow waveguide structure
- H01P1/2084—Cascaded cavities; Cascaded resonators inside a hollow waveguide structure with dielectric resonators
- H01P1/2086—Cascaded cavities; Cascaded resonators inside a hollow waveguide structure with dielectric resonators multimode
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01P—WAVEGUIDES; RESONATORS, LINES, OR OTHER DEVICES OF THE WAVEGUIDE TYPE
- H01P1/00—Auxiliary devices
- H01P1/20—Frequency-selective devices, e.g. filters
- H01P1/207—Hollow waveguide filters
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Abstract
A resonator apparatus for use in a radio frequency filter has dielectric resonating means creating or supporting at least three resonant modes. The resonator apparatus is arranged such that only two of the at least three resonant modes are degenerate and said at least three resonant modes coincide or substantially coincide at a particular frequency or set of frequencies. The resonating means may be provided in a cavity of a housing and the at least three resonant modes may be achieved by adjusting the ratio of the cavity diameter with respect to the height of the cavity, by adjusting the ratio of the diameter of the resonating means with respect to the height of the resonating means and/or by adjusting the cavity diameter and/or height with respect to the resonating means diameter and/or height. The at least three resonant modes include a pair of hybrid modes (HE) and a transverse magnetic mode (TM mode). The resonating means may have one or more recesses, slots and/or channels defined at or adjacent one or more peripheral edges or surfaces of it.
Description
Resonator Apparatus and Method of Use Thereof
This invention relates to filter apparatus and to a method of use thereof. It also relates to resonator apparatus for use in filter apparatus, and a method of using resonator apparatus.
Filter apparatus is typically used in telecommunication systems to compensate for disturbances, such as interference, that may affect one or more radio frequency (RF) signals being sent and/or received by the telecommunication system. The filter apparatus is designed to remove umvanted components from the transmit and/or receive signals and/or enhance the desired transmit and/or receive signals.
An example of conventional RF or microwave filter apparatus typically includes a conductive housing defining one or more resonant cavities therein, with one or more resonators located in each cavity. A resonator is an electronic component that exhibits resonance for a narrow range of frequencies. Two or more resonators within the filter are typically electromagnetically coupled together to provide the filter with a required set of performance characteristics.
An example of conventional resonator apparatus 2 for use in an RF filter is shown in figure 1. The apparatus 2 is in the form of a metal combline filter and comprises a cavity 4 in which a combline resonator 6 is provided. Resonator 6 is a single mode resonator and is an industry standard for use in cellular radios. Problems with the use of this type of resonator apparatus is that the resulting filter is relatively large in size and is expensive to produce.
An example of further known resonator apparatus 102 for use in an RF filter is disclosed in British Patent Application GB1303086.1 and is shown in figure 2. The apparatus 102 is in the form of a dielectric rod resonator and comprises a cavity 104 in which a dielectric rod 106 formed from ceramic is provided. Resonator 106 is a single mode resonator resonating in a transverse magnetic (TM) mode. This type of resonator apparatus suffers from similar problems to that set out above.
A yet further example of known resonator apparatus 108 for use in an RF filter is disclosed in British Patent Application GB1716629.9 and is shown in figure 3. The apparatus includes a cavity 104 as previously described, but the dielectric rod 110 provided in the cavity has a dual resonant mode. By providing resonator apparatus having two resonant modes, this reduces the size of the resulting resonator apparatus (i.e. a resonator having two resonating modes can be fitted into a cavity normally only used for a resonator providing a single resonant mode).
In an attempt to reduce the size of the resonator and filter apparatus even further, it is known to provide resonator apparatus wherein the dielectric rod located in the cavity has three resonant modes (triple mode resonator). Conventionally, these three resonant modes are degenerate. In this patent application, degenerate modes are defined as two or more modes that are orthogonal or substantially orthogonal to each other (i.e. each mode is provided in X, Y, Z orientations within a cavity), each resonant mode having the same or substantially similar electromagnetic field patterns differing mainly in that each is a rotation and/or reflection of the other(s), and the modes resonate at the same or substantially the same frequency . Resonators that exhibit three degenerate modes tend to be rather large and still results in the resonator apparatus, and therefore the resulting filter apparatus, being relatively large in size.
It is therefore an aim of the present invention to provide alternative filter apparatus that overcomes the abovementioned problems.
It is a further aim of the present invention to provide alternative resonator apparatus for use in filter apparatus that overcomes the abovementioned problems.
It is a yet further aim of the present invention to provide a telecommunications system including alternative filter apparatus.
It is a yet further aim of the present invention to provide a method of using and/or assembling filter apparatus, resonator apparatus and/or a telecommunications system.
According to a first aspect of the present invention there is provided resonator apparatus for use in radio frequency filter apparatus, said resonator apparatus comprising dielectric resonating means creating or supporting at least three resonant modes, and wherein said resonator apparatus is arranged such that only two of the at least three resonant modes are degenerate and said at least three resonant modes coincide or substantially coincide at a particular frequency or set of frequencies.
Thus, by providing resonator apparatus wherein the at least three resonant modes coincide or substantially coincide at a particular frequency or set of frequencies, but only two of the modes are degenerate, rather than being a triple mode resonator having three degenerate modes as in the prior art, this significantly alters the resonator design and can reduce the size of the resonator apparatus and also improve the Q factor of the resonator apparatus.
Preferably the at least three resonant modes are at the same or substantially the same resonant frequency or frequency range.
Preferably the resonant frequency or frequencies of the resonating means are within the electromagnetic spectrum range of frequencies.
Preferably the resonating means are provided in a space or cavity, such as for example a resonator cavity defined in a housing or filter apparatus housing.
Preferably the resonating means consists of a single resonator, and said single resonator creates or supports the at least three resonant modes.
In one embodiment the at least three resonant modes are achieved by adjusting the ratio of the cavity diameter with respect to the height of the cavity, by adjusting the ratio of the diameter of the resonating means with respect to the height of the resonating means and/or by adjusting the cavity diameter and/or height with respect to the resonating means diameter and/or height.
Preferably the cavity diameter is the distance between opposing side walls which define, at least in part, the cavity.
Preferably the cavity height is the distance between a top of the cavity and a base of the cavity. Further preferably the base and top of the cavity are opposite to each other.
Preferably the height of the resonating means is the distance between a top and base of the resonating means.
Preferably the diameter of the resonating means is the distance between opposing side walls of the resonating means.
Preferably the cavity in which the resonating means is located comprises a base on which the resonating means is located, an opening opposite to the base via where the resonating means is inserted into the cavity in use, and wherein the resonating means is located on the base and protrudes towards the opening.
Preferably the side walls of the cavity are provided between a base and an opening of the cavity.
Preferably a lid or cover is provided over the opening of the cavity in use.
Preferably the resonating means has a base which is located on a surface of the cavity in use, and a top which is opposite to the base.
Preferably the top of the resonating means is nearest to the opening, lid or cover of the cavity.
Preferably the resonating means has side walls provided between the base and top thereof.
Preferably the resonating apparatus can be arranged such that there will be a frequency or frequency range at which at least three resonant modes of the resonating means will coincide or substantially coincide (i.e. be equal or substantially equal).
Preferably one of the at least three resonant modes is a nondegenerate mode.
Preferably the at least three resonant modes will include a pair of hybrid modes (HE modes), together with a transverse magnetic (TM mode).
Preferably the pair of HE modes are a pair of HEn modes or HE11X and HE11Y
Preferably the TM mode is a TM01 mode.
Preferably the HE11X mode, the HE11Y mode and the TM01 mode occur at the same or substantially the same frequency or frequency range.
Preferably the resonating means is cylindrical or substantially cylindrical in shape.
Preferably the resonating means is joined to, supported by and/or in abutting relationship with a base of the cavity or space of the resonator apparatus.
In one embodiment the resonating means is joined to a wall defining the cavity by one or more screws, one or more screws formed from electrical insulating material or having an electrical insulating outer surface, solder, adhesive, one or more inter-engaging members and/or the like.
Preferably the resonating means is provided a spaced distance apart from a top or lid of the cavity or space of the resonator apparatus. Thus, in one example, a space or an air gap is provided between a top surface of the resonating means and an opposing lower surface of the lid of the cavity or space.
Preferably the space or air gap between the top of the resonating means and the top or lid of the cavity is less than or equal to 2mm, and further preferably is less than or equal to 1.65mm.
In one embodiment the cavity or space of the resonator apparatus in which the resonating means is located is cylindrical or substantially cylindrical. However, the cavity or space of the resonator apparatus could be any shape as required.
Preferably the base of the cavity or space is opposite or substantially opposite to the lid or top of the cavity or space.
Preferably the resonator apparatus includes an input coupling and an output coupling.
Further preferably the input coupling is a coupling for allowing the passage of one or more radio frequency signals into the apparatus in use, and the output coupling is a coupling for allowing the passage of one or more radio frequency signals out of the apparatus in use.
Preferably the input and output couplings are arranged such that at least one, and further preferably at least two, transmission zeroes are provided at finite frequencies.
Preferably the input coupling and output coupling are arranged to be at an angle of approximately 80-110 degrees to each other, and further preferably to be at 90 or substantially 90 degrees to each other.
Preferably the dielectric resonating means includes or is formed from ceramic material.
In one example the dielectric material is in the form a ceramic puck.
Preferably the relative dielectric constant of the dielectric material or ceramic is 30-100.
In one embodiment at least one layer or coating of electrically conductive material is provided on an outer or outermost surface of the dielectric material of the resonating means. Thus, in one example, the resonating means formed from or including a dielectric material optionally includes an electrically conductive coating and/or layer provided on at least one external surface thereof.
In one embodiment an electrically conductive coating and/or layer can be provided on one or more walls defining the cavity in which the resonating means are located, such as for example, attached to the base of the cavity by soldering or other attachment means.
In one embodiment the one or more walls defining the cavity in which the resonating means are located is formed from an electrically conductive material.
In one embodiment the resonating means can be any or any combination of a solid object, an annular object, a regular shaped object, an irregular shaped object, a symmetrical object, an asymmetrical object and/or the like.
In one embodiment the resonating means is located on a base of a cavity defined in a body portion of filter apparatus.
Preferably the resonating means has one or more recesses, slots and/or channels defined at or adjacent one or more peripheral edges or surfaces of the same.
Preferably the one or more recesses, slots and/or channels have a longitudinal axis which are arranged parallel or substantially parallel to a longitudinal axis of the resonating means, height of the resonating means (i.e. a distance between a top and base of the resonating means) and/or height of the cavity in which the resonating means is located.
Preferably the one or more recesses, slots and/or channels are defined along the entire or substantially entire height of the resonating means (i.e. along the entire height of the resonating means between a top and base of the resonating means).
Preferably the one or more recesses, slots and/or channels are open to the top and/or base surfaces of the resonating means.
Preferably a base of the resonating means is located on a wall of the resonator apparatus defining a base of the cavity or space.
Preferably a top of the resonating means is located a spaced distance apart from a wall of the resonator apparatus defining a lid or top of the cavity or space.
Preferably the base of the resonating means is opposite or directly opposite to the top of the resonating means.
Preferably one or more side walls of the resonating means defined between the top and base of the resonating means are a spaced distance apart from one or more walls of the resonator apparatus defining one or more side walls of the cavity or space.
Preferably the top and/or base surface of the resonating means is a flat, substantially flat, planar or substantially planar surface.
In one embodiment the one or more recesses, slots and/or channels are of the same or substantially the same shape.
In one embodiment the one or more recesses, slots and/or channels are of different shapes.
In one embodiment the one or more recesses, slots and/or channels are equidistance apart or substantially equidistance apart. However, in one example, the one or more recesses, slots and/or channels can be different distances apart.
In one embodiment the one or more recesses, slots and/or channels can have any suitable cross sectional shape, such as semi-circular, square, rectangular, triangular and/or the like.
Preferably the dimensions of the one or more recesses, slots and/or channels can be the same or different to each other.
In one embodiment the input coupling and/or output coupling is physically connected to the resonating means, such as for example via solder.
In one embodiment the input coupling and/or output coupling is electrically or electromagnetically coupled to the resonating means, and may or may not be physically connected to the resonating means.
In one embodiment the input coupling and/or output coupling includes at least one pin member protruding transverse, perpendicular or substantially perpendicular to a side wall defining the cavity.
Further preferably at least one transformer member is provided at an end of the pin member furthest from the side wall defining the cavity.
Preferably the at least one transformer member is provided parallel or substantially parallel to a height of the cavity and/or height or longitudinal axis of the resonator means.
Preferably a first end of the at least one transformer member is in contact with the base of the cavity.
Preferably a second end of the at least one transformer member is a spaced distance apart from a top or lid of the cavity.
Preferably the at least one transformer member is equal to or less than 1mm from a top or lid of the cavity.
Preferably the cavity of the resonating means is defined in a body portion of filter apparatus, in a body portion formed from or coated in electrically conductive material, metal, and/or the like.
In one embodiment a plurality of resonator apparatus are cascaded or coupled together to form filter apparatus.
In one embodiment one or more tuning means are provided on or associated with the resonator apparatus.
Preferably at least three tuning means are provided; one tuning means for each resonator mode of the resonating means.
In one embodiment at least four tuning means are provided; one tuning means for each resonator mode of the resonating means and at least one further tuning means for tuning one or more couplings between the resonator modes.
Preferably the tuning means includes one or more tuning rods or screws, one or more metallic tuning rods or screws and/or one or more dielectric tuning rods or screws.
Preferably the tuning means are provided in or through a lid or top of the resonator apparatus and/or filter apparatus.
In one embodiment the tuning means are positioned in the resonator apparatus and/or filter apparatus so as to be located directly over and/or in alignment with the resonating means with which they are associated with.
In one embodiment the tuning means are positioned in the resonator apparatus and/or filter apparatus so as to be directly over and/or in alignment with the one or more recesses, slots and/or channels of the resonating means.
According to a second aspect of the present invention there is provided filter apparatus including resonator apparatus.
Preferably the filter apparatus includes at least one resonator apparatus located in a cavity defined within the filter apparatus.
Preferably the filter apparatus includes input means or an input port and output means or an output port for allowing one or more radio frequency signals to enter and/or leave the apparatus respectively.
According to a yet further aspect of the present invention there is provided a telecommunication system.
According to one aspect of the present invention there is provided a method of using resonator apparatus, said resonator apparatus comprising dielectric resonating means, and wherein said method includes the steps of arranging the resonating means so as to create or support at least three resonant modes; only two of the at least three resonant modes being degenerate and said at least three resonant modes coinciding or substantially coinciding at a particular frequency or set of frequencies.
According to one aspect of the present invention there is provided a method of using or assembling filter apparatus including resonator apparatus.
According to one aspect of the present invention there is provided a method of using or assembling a telecommunication system.
Embodiments of the present invention will now be described with reference to the following figures, wherein:
Figure 1 (PRIOR ART) is a simplified view of resonator apparatus comprising a single mode metal combline resonator;
Figure 2 (PRIOR ART) is a simplified view of resonator apparatus comprising a single mode dielectric rod resonator;
Figure 3 (PRIOR ART) is a simplified view of resonator apparatus comprising a dual mode dielectric rod resonator;
Figure 4 is a simplified view of resonator apparatus according to an embodiment of the present invention comprising a triple mode electric rod resonator;
Figures 5a and 5b show a perspective view and a side view of resonator apparatus according to an embodiment of the present invention respectively;
Figures 6a and 6b show the electric field and the magnetic field for the resonator apparatus in figure 5a on which an electromagnetic simulation (finite-element method field simulation) has been undertaken respectively for the HEllx mode;
Figures 7a and 7b show the electric field and the magnetic field for the resonator apparatus in figure 5a on which an electromagnetic simulation (finite-element method field simulation) has been undertaken respectively for the HElly mode;
Figures 8a and 8b show the electric field and the magnetic field for the resonator apparatus in figure 5a on which an electromagnetic simulation (finite-element method field simulation) has been undertaken respectively for the TM01 mode;
Figure 9 shows a perspective view of the resonator apparatus in figures 5a and 5b with the input and output couplings shown;
Figure 10 shows a perspective view of filter apparatus including resonator apparatus according to an embodiment of the present invention with external input and output filter couplings shown;
Figure 11 is a graph showing the results for three resonator modes of resonator apparatus according to an embodiment of the present invention using a finite-element method field simulation, when the dimensions of the resonator means and the diameter of the resonator cavity are kept constant and the height of the resonator cavity is changed as a function of cavity diameter to cavity height;
Figure 12 is a graph showing the results for three resonator modes of resonator apparatus according to an embodiment of the present invention using a finite-element method field simulator when the dimensions of the resonator cavity are kept constant and the diameter of the resonator means is changed as a function of resonator cavity diameter to resonator means diameter;
Figure 13 is a graph showing the simulated response of the three resonant mode resonator apparatus.
Referring initially to figure 4, resonator apparatus 200 according to an embodiment of the present invention is shown. The apparatus 200 has three coinciding resonant modes; a HEllx mode, a HElly mode and a TM01 mode.
The HEllx and HE11Y modes are degenerate modes and are located 90 degrees to each other. The TM01 mode is a non-degenerate mode.
The resonator apparatus 200 comprises a cavity 202, which would normally be defined in a metallic housing and/or a housing wherein at least the walls defining the interior of the cavity 202 are provided with an electrical conductive coating thereon. In this example the cavity 202 is defined by a base wall 204, side walls 206 and a top or lid 208.
Resonator means in the form of a ceramic puck 210 is located in cavity 202. Puck 210 has a base 212 that is in contact with the base wall 204 of the cavity, side walls 214 that are a spaced distance from the side walls 206 of the cavity, and a top 216 that is a spaced distance below the top or lid 208 of the cavity.
The dimensions of the ceramic puck with respect to the cavity are critical to the provision of the three resonator modes coinciding (or substantially coinciding) at a set frequency or frequency range. It will be appreciated that the aspect ratio of the cavity and puck in figure 4 is different to that in the prior art dual mode or single mode dielectric resonator apparatus shown in figures 2-3. It should be noted that in the prior art shown in figures 2 and 3, the dimensions of the dielectric resonator and the cavity are typically chosen such that other resonant modes occur as high in frequency as possible in order to maximise the extent of the stopband of any filter comprising such resonators. The dimensions of the ceramic puck and/or the cavity of the present invention can be adjusted such that the desired frequency or frequency range where all three resonator modes coincide or substantially coincide is achieved.
The ceramic puck 210 is shown as being cylindrical in the illustration, but the puck could be other shapes if required. The cavity 202 is also shown as being cylindrical in the illustration but could be other shapes if required. The puck 210 and cavity 202 can be the same shape as each other but do not need to be the same shape as each other.
Referring to figures 5a and 5b, there is illustrated an embodiment of the resonator apparatus 200 wherein elongate recesses 218 are defined around the peripheral edge of the puck 210. The recesses 218 are equal to the height of the puck 210 and are provided the entire length of the puck 210 between the base 214 and top 216, such that each recess has an opening in both the base and top surface of the puck. A longitudinal axis of each recess 218 is parallel or substantially parallel to a longitudinal axis of the puck 210.
In the illustration, the recesses 218 are provided equidistance apart around the peripheral edge of puck 210 but the recesses could be provided at different distances apart if required. In addition, the depth of the recess in a radial direction of the puck 210 could be adjusted if required.
In this embodiment, puck 210 is secured to the base 204 of the cavity via an electrically insulating connection member. In this example, the electrical insulating connection member is a plastic screw 220 which is located in an aperture in the puck and which extends from the top 216 of the puck to the base 214 of the puck.
Example 1
A finite-element method field simulator (HFSS) was used to study the electrical and magnetic fields of the resonator apparatus of the present invention shown in figures 5a and 5b in order to demonstrate the provision of the three different resonant modes; HEllx, HEn TM01.
The metallic walls defining the resonator cavity were chosen to be slightly larger than the dimensions of the resonating means in this example. The resonating means comprised a cylindrical ceramic puck having a diameter of 20mm and a height of 10mm, with permittivity of 44 and loss tangent of 4.105. The puck was in direct contact with the base of the cavity and there was a small air gap between the top of the puck and the lid of the cavity.
The metallic walls defining the resonator cavity were formed from copper and had an internal diameter (D) of 30mm, with an electrical conductivity of 4xl07 S/m.
Figures 6a and 6b show the electrical field and the magnetic field respectively for the HEllx resonator mode using the simulation.
Figures 7a and 7b show the electrical field and the magnetic field respectively for the HElly resonator mode using the simulation.
Figures 8a and 8b show the electrical field and the magnetic field respectively for the TM01 resonator mode using the simulation.
It is noted that the electrical field of the three resonator modes xvas maximum near the top flat surface of the resonator puck 210. The density of the electrical field in the TM resonator mode was found to be significantly larger than the degenerate HE resonator modes. This drives the TM resonator mode down in frequency and facilitates strong inter-resonator couplings between the three resonator modes.
The effect of adjusting the diameter (d) of the resonator puck 210, while keeping the diameter (D) of the cavity constant at 30mm is shown in figure 12. Resonator frequency in GHz is shown on the Yaxis and the cavity diameter (D) to ceramic puck diameter (d) is shown on the X-axis, where D = 30mm. The height of the cavity was kept constant at 11.35mm. It can be seen that an increase in the resonator/ceramic puck diameter drives the frequency of the three resonator modes (HEllx, HEn TM01) down. The unloaded Q of the degenerate mode is found to be significantly improved.
The effect of adjusting the height (L) of the cavity 202 (i.e. the distance between the base 204 and lid 208 of the cavity) while keeping the dimensions of the resonator/ceramic puck and the diameter (D) (i.e. the distance between opposing side walls of the cavity) of the cavity constant is shown in Figure 11. Resonator frequency in GHz is shown on the Y-axis and the cavity diameter (D) to the height of the cavity (L) is shown on the X-axis, wherein D = 30mm. It can be seen that the effect of reducing the cavity height (i.e. the distance between the top 208 and base 204 of the cavity) with respect to the puck 210 was found to drive the TM resonator mode down in frequency while not significantly affecting the frequency of the fundamental degenerate HEn resonator modes. It also reduced the unloaded Q factor of the resonator.
Thus, the results of the simulation demonstrate that the resonant frequency and Q factor of the resonator apparatus according to the present invention is largely determined by the ceramic puck permittivity and diameter, and the height and diameter of the cavity defined in the metallic housing.
Figure 9 shows the resonator apparatus 200 in figures 5a-5b with an input coupling 222 and an output coupling 224. Each coupling 222, 224 includes a pin member 226 protruding inwardly of the cavity 202 from a side wall 206 of the cavity. The pin member 226 is located a spaced distance from the base 204 of the cavity and the top or lid 208 of the cavity. A longitudinal axis of the pin member 226 is provided parallel to base 204 of the cavity. A transformer member 228 is located at the end of the pin member 226 closest to the puck 210. A longitudinal axis of transformer member 228 is provided parallel to the height or longitudinal axis of the puck 210. A base of the transformer member 228 is in contact with the base 204 of the cavity and a top of the transformer member is a spaced distance apart from the top or lid 208 of the cavity. Preferably the space between the top of the transformer member and the top or lid 208 of the cavity is less than 1mm. This allows coupling into the high field strength located at the top of the puck 210.
In the illustration, the transformer member is aligned with a recess 218 of the puck 210 and is a spaced distance apart from the puck 210 and recess 218.
The input and output couplings 222, 224 are provided at 90 degrees in the illustration but the couplings could be provided at different angles to each other if required.
Figure 10 is an example of filter apparatus 300 according to an embodiment of the present invention consisting of one resonator apparatus 200 having a triple resonator mode. The apparatus 300 includes a filter input coupling 302 and a filter output coupling 302.
Figure 13 shows simulation plots for the filter shown in figure 10. Sil refers to the return loss of the filter and the three nulls in the curve show that a third order filter response is indeed obtained from a single physical resonator. S21 refers to the transmission loss and shows that the filter is low loss in the passband and a steep rejection characteristic is obtained with the two nulls in the S21 curve corresponding to two transmission zeroes that are achieved by coupling between the resonant modes.
Claims (27)
1. Resonator apparatus for use in radio frequency filter apparatus, said resonator apparatus comprising dielectric resonating means creating or supporting at least three resonant modes, and wherein said resonator apparatus is arranged such that only two of the at least three resonant modes are degenerate and said at least three resonant modes coincide or substantially coincide at a particular frequency or set of frequencies.
2. Resonator apparatus according to claim 1 wherein the resonating means are provided in a cavity of a housing, and said at least three resonant modes are achieved by adjusting the ratio of the cavity diameter with respect to the height of the cavity, by adjusting the ratio of the diameter of the resonating means with respect to the height of the resonating means and/or by adjusting the cavity diameter and/or height with respect to the resonating means diameter and/or height.
3. Resonator apparatus according to claim 1 wherein one of the at least three resonant modes are non-degenerate.
4. Resonator apparatus according to claim 1 wherein the at least three resonant modes include a pair of hybrid modes (HE modes) and a transverse magnetic mode (TM mode).
5. Resonator apparatus according to claim 4 wherein the pair of HE modes are a pair of HEn modes or HE11X and HE11Y modes, and wherein the TM mode is a TM01 mode.
6. Resonator apparatus according to claim 1 wherein one or more walls defining the cavity in which the resonating means is located is formed from and/or has one or more layers and/or coatings of electrically conductive material.
7. Resonator apparatus according to claim 1 wherein the resonating means and/or the cavity in which the resonating means is located is cylindrical or substantially cylindrical.
8. Resonator apparatus according to claim 1 wherein the resonating means is joined to, supported by and/or in abutting relationship with a base of the cavity of the apparatus.
9. Resonator apparatus according to claim 1 wherein the resonating means is joined to a wall defining the cavity by one or more screws, one or more screws formed from electrical insulating material or having an electrically insulating outer surface; solder; adhesive; or one or more inter-engaging members.
10. Resonator apparatus according to any preceding claim wherein the resonating means is provided a spaced distance apart from a top or lid of the cavity of the apparatus.
11. Resonator apparatus according to claim 10 wherein the space or gap between the top of the resonating means and the top or lid of the cavity is less than or equal to 2mm.
12. Resonator apparatus according to any preceding claim including an input coupling and an output coupling.
13. Resonator apparatus according to claim 12 wherein the input and output couplings are arranged such that at least one transmission zeroes are provided at finite frequencies and/or wherein the input and output couplings are arranged to be at an angle of approximately 80-110 degrees.
14. Resonator apparatus according to any preceding claim wherein the dielectric resonating means includes or is formed from ceramic material, or is a ceramic puck.
15. Resonator apparatus according to any preceding claim wherein at least one layer or coating of electrically conductive material is provided on an outer surface of the dielectric resonating means.
16. Resonator apparatus according to claim 16 wherein the at least one layer or coating of electrically conductive material is provided on a top surface of the resonating means or a surface of the resonating means opposite to and separated from a lid or cover of the apparatus.
17. Resonator apparatus according to claim 16 wherein the at least one layer or coating of electrically conductive material is provided on a base surface of the resonating means and is attached to the base of the cavity by soldering or other attachment means.
18. Resonator apparatus according to any preceding claim wherein the resonating means has one or more recesses, slots and/or channels defined at or adjacent one or more peripheral edges or surfaces of the same.
19. Resonator apparatus according to claim 18 wherein the one or more recesses, slots and/or channels have a longitudinal axis which are arranged to be parallel to a longitudinal axis of the resonating means and/or a longitudinal axis of the cavity in which the resonating means are located in use.
20. Resonator apparatus according to claims 18 or 19 wherein the one or more recesses, slots and/or channels are defined along the entire or substantially entire height of the resonating means.
21. Resonator apparatus according to any preceding claim wherein the input coupling and/or output coupling is electrically or electromagnetically coupled to the resonating means and/or is physically connected to the resonating means.
22. Resonator apparatus according to claim 21 wherein the input coupling and/or output coupling includes at least one pin member protruding transverse or perpendicular to a side wall of the cavity in which the resonating means is located in use, and at least one transformer member is provided at an end of the pin member furthest from the side wall defining the cavity.
23. Resonator apparatus according to claim 22 wherein the at least one transformer member is provided parallel or substantially parallel to a height of the cavity and/or height or longitudinal axis of the resonator means.
24. Resonator apparatus according to claim 23 wherein a first end of the at least one transformer member is in contact with a base of the cavity in which the resonating means is located in use, and a second end of the at least one transformer member is a spaced distance apart from a top or lid of the cavity.
25. Resonator apparatus according to any preceding claim wherein a plurality of resonator apparatus are cascaded together to form filter apparatus.
26. Resonator apparatus according to any preceding claim wherein at least three tuning means are provided on or associated with the resonator apparatus; one for each of the at least three resonator modes of the resonating means.
27. A method of using resonator apparatus, said resonator apparatus comprising dielectric resonating means, and wherein said method includes the steps of arranging the resonating means so as to create or support at least three resonant modes; only two of the at least three resonant modes being degenerate and said at least three resonant modes coinciding or substantially coinciding at a particular frequency or set of
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GBGB1719975.3A GB201719975D0 (en) | 2017-11-30 | 2017-11-30 | Filter apparatus and method of use thereof |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| GB201819516D0 GB201819516D0 (en) | 2019-01-16 |
| GB2570765A true GB2570765A (en) | 2019-08-07 |
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Family Applications (2)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| GBGB1719975.3A Ceased GB201719975D0 (en) | 2017-11-30 | 2017-11-30 | Filter apparatus and method of use thereof |
| GB1819516.4A Withdrawn GB2570765A (en) | 2017-11-30 | 2018-11-30 | Resonator apparatus and method of use thereof |
Family Applications Before (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| GBGB1719975.3A Ceased GB201719975D0 (en) | 2017-11-30 | 2017-11-30 | Filter apparatus and method of use thereof |
Country Status (1)
| Country | Link |
|---|---|
| GB (2) | GB201719975D0 (en) |
Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN204885383U (en) * | 2015-08-19 | 2015-12-16 | 江苏吴通通讯股份有限公司 | Three mould medium chamber body wave filter |
-
2017
- 2017-11-30 GB GBGB1719975.3A patent/GB201719975D0/en not_active Ceased
-
2018
- 2018-11-30 GB GB1819516.4A patent/GB2570765A/en not_active Withdrawn
Patent Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN204885383U (en) * | 2015-08-19 | 2015-12-16 | 江苏吴通通讯股份有限公司 | Three mould medium chamber body wave filter |
Non-Patent Citations (1)
| Title |
|---|
| Mustafa S. Bakr et al; "2016 16th Mediterranean Microwave Symposium (MMS)"; 5th January 2017; IEEE; "Triple mode dielectric-loaded cavity band pass filter" * |
Also Published As
| Publication number | Publication date |
|---|---|
| GB201719975D0 (en) | 2018-01-17 |
| GB201819516D0 (en) | 2019-01-16 |
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