A quarter structural substract integrated waveguide dual-passband electrically tunable filter
Technical field
The present invention relates to microwave and millimeter wave technical field is belonged to, specifically a kind of a quarter structural substract integrated waveguide is double
Passband electrically tunable filter.
Background technique
With the continuous development of Modern wireless communication, in different frequency range, there is a large amount of radio communication services, especially with
The development of software and radio technique, there is an urgent need to develop with before multiband covering power and the tunable radio frequency of functional characteristic
End.Radio-frequency filter is the important component of wireless communication RF front end, is widely used in radiofrequency signal other than frequency band
Inhibit, reaches frequency band selection, inhibit Image interference, reduce the purpose of picking crosstalk, there is the tunable characteristic of frequency response
Tunable radio frequency filter by be future broadband wireless communication systems important support, according to GSM, multiple communication standards such as CDMA, LTE
Division, have different index requests to filter of the work under different systems.Traditional solution is using radio frequency
The filter of switch selection corresponding index, this all forms burden to the volume and cost of communication system, and integrated with needing
Communication standard it is more and more, the filter of suitching type seems more and more undesirable.Relative to can not tunable filter and radio frequency open
The combination of pass realizes that communication standard is switching to following development trend using tunable filter.
Tunable radio frequency passive device such as tunable filter, wave beam adjustable antenna etc. is most early in the armies such as electronic countermeasure, radar electricity
It is used in equipment.It is adjustable that common adjustable method is divided into resonator mechanical deformation, including mechanical structure is adjustable, piezoelectricity is adjustable
Deng;Resonator loads adjustable element, including semiconductor variable capacitance diode, MEMS (Micro Electrol Mechanical
Systems) tunable capacitor and inductance, ferro-electric tunable appearance, liquid crystal tunable capacitor, controllable impedance etc.;Resonator load is tunable
Switch element, such as MEMS RF switch, PIN switch, mechanical switch;And dielectric resonator material is adjustable, such as yttrium iron pomegranate
YIG (yttrium iron garnet), ferroelectricity is adjustable etc..Over time, tunable optic filter is towards small-sized
Change, planarization, lightweight, high integration direction develop.Due to the introducing of tuned cell, the loss of tunable optic filter is usual
Substrate integrated waveguide technology is introduced, it is compared to gold greater than general filter in order to improve the loss characteristic of tunable optic filter
Belonging to waveguide and planar microstrip structure, its Q value of substrate integration wave-guide is high, and light-weight, loss is small, and power capacity is big, and it is at low cost, easily
In integrated with other planar circuits.The substrate integrated wave guide structure of a quarter structure be substrate integrated wave guide structure four/
One, very have the function of miniaturization.
Summary of the invention
In view of the foregoing deficiencies of prior art, the purpose of the present invention is to provide a kind of a quarter structural substract collection
At waveguide dual-passband electrically tunable filter.
For achieving the above object, technical solution of the present invention is as follows:
A kind of a quarter structural substract integrated waveguide dual-passband electrically tunable filter, including medium substrate, medium substrate
The a quarter of upper surface covers the lower metal copper of steel structure, medium substrate lower surface;
The a quarter covers steel structure and is equipped with the plated-through hole for constituting substrate integration wave-guide, and a quarter covers copper knot
Structure lower left side is 50 ohm of input microstrip lines, and the top of 50 ohm of input microstrip lines, the metallization for constituting substrate integration wave-guide are logical
A L-type slot is provided with as co-planar waveguide input terminal on the right side of hole;A quarter, which is covered inside steel structure, has one on the right side of L-type slot
Complimentary square spiral resonant ring;Covering on the right side of steel structure in a quarter is 50 ohm of transition microstrip lines;A quarter covers steel structure
The uniform plated-through hole of a row of edge side runs through upper surface copper-clad, medium substrate, lower layer's copper-clad, in this way by upper layer
Copper-clad, medium substrate, lower layer's copper clad layers and the edge uniform plated-through hole of one row together form a quarter and cover copper
Structural substract integrated waveguide.
It is a large square metal flat on the right side of 50 ohm of transition microstrip line, large square metal flat top center connects
50 ohm of output microstrip lines are connect, two sides are equipped with a pair of of L-type slot, 50 ohm of output microstrip lines or so to 50 ohm of transition microstrip lines up and down
Two sides are equipped with a pair of of L-type slot, and four right angles of large square metal flat are cut away by four small squares, leave four notch;Greatly
Square metal planar central has a undercut type perforated metal piece, and center is equipped with center via hole, in undercut type perforated metal piece
Lower section is equipped with a square metal piece, is welded with conventional capacitive between undercut type perforated metal piece and square metal piece;
It is biasing circuit that a quarter, which is covered below steel structure and 50 ohm of input microstrip lines, comprising: six rectangular gold
Belong to pad, current-limiting resistance, the second rectangular metal welding are welded between the first rectangular metal pad and the second rectangular metal pad
Be welded with choke induction between disk and third square metal pad, the second rectangular metal pad and square metal pad it
Between be welded with ground capacity, capacitance is welded between third square metal pad and the 5th square metal pad,
It is welded with varactor between three rectangular metal pads and hexagon metal pad, in hexagon metal pad and first
Square metal pad lower part is respectively equipped with the first rectangle perforated metal piece, the second rectangle perforated metal piece, the first rectangle punching gold
Belong to piece, the second rectangle perforated metal on piece is equipped with ground metallization through-hole, the first rectangular metal pad and the second rectangle punching gold
Belonging to is DC power supply between piece, and DC power supply is biased circuit by the first rectangular metal pad and is beaten by the second rectangle
Mesoporous metal piece is grounded, and hexagon metal pad and the first rectangle perforated metal piece are connected for being grounded;
5th square metal pad connection a quarter covers the center of the complimentary square spiral resonant ring in steel structure and general
It is powered and holds, third square metal pad is connected by capacitance below, a quarter covers steel structure and large square metal is flat
It is isolated between the biasing circuit by parallel isolation plated-through hole below face.
It is preferred that a quarter covers steel structure and the junction of 50 ohm of transition microstrip lines is straight equipped with a metal
Angle triangle.
It is preferred that the first rectangular metal pad, the second rectangular metal pad, third square metal pad, the 6th
Square metal pad is located in same horizontal line, and the 5th square metal pad is located above third square metal pad, four directions
Shape metal pad is located at below the second rectangular metal pad.
It is preferred that the complimentary square spiral resonant ring includes inner ring and outer rings, wherein inner ring connects with outer ring,
The width and spacing of two resonant rings are equal.
The invention has the benefit that 1. present invention use substrate integrated waveguide technology, compared to microstrip line, its Q value is high,
Light-weight, loss is small, and power capacity is big, at low cost, is easy to integrated with other planar circuits.A quarter covers steel structure substrate collection
It is substrate integration wave-guide along central cross and a quarter structure obtained from longitudinal cut away at waveguide, structure greatly reduces, and has
There is miniaturization.2. due to using substrate integrated waveguide technology, by the equivalent dimension and resonance frequency of substrate integration wave-guide
Relationship it is found that resonance frequency is smaller, size is bigger, so the low-frequency filter using substrate integrated waveguide technology is very unlikely to
It realizes, one advantage of the present invention is using complement helical resonant ring, so that resonance frequency strongly reduces, therefore humorous by complement helical
Vibration ring controls its resonance frequency, so that the size of external a quarter structural substract integrated waveguide greatly reduces.3. the present invention by
A quarter covers steel structure substrate integration wave-guide and complimentary square spiral resonant ring generates the first passband, and has a transmission zero
Point, and respectively have a pair of of L-type slot by 50 ohm of transition, output microstrip line both sides, the effect of this four L-type slots is the electricity to filter
Flow distribution forms perturbation, has motivated bimodulus, generates the second passband, and has good harmonics restraint to act on, large square metal flat
Four right angles cut away by four small squares be in order to reduce impedance so that resonance frequency reduce.4. the present invention is in large square
There are a undercut type perforated metal piece and center via hole in metal flat center, has a rectangular gold in undercut type perforated metal piece lower part
Belong to piece, is that will weld a capacitor between undercut type perforated metal piece and square metal piece here, it is therefore an objective in applied bias electricity
Under pressure effect, inhibit higher hamonic wave effect.5. the present invention is transitioned into after 50 ohm microstrips using L-type coplanar waveguide form humorous
Shake chamber, can be significantly reduced reflection;A quarter, which is covered on the downside of steel structure, has a row along the metallization VIA of parallelism structural, mesh
Be the performance for reducing pad and a quarter and covering the coupling between steel structure and large square metal flat and influencing filter;
Voltage enters vector network analyzer by substrate integration wave-guide and damages in order to prevent, is welded with also between pad
Choke induction, choke induction are in order to every the logical direct current of exchange.6. the present invention can improve complement helical resonant ring and requiring
Radius, the different frequency range of the length and width of four L-type slots, control passband, have a wide range of applications market.The filter
With small in size, insertion loss is low, centre frequency is continuously adjustable, Out-of-band rejection is high, load DC feedback is convenient, tuned speed
Fastly, the features such as tuning facilitates.
Detailed description of the invention
Fig. 1 is the top view of a quarter structural substract integrated waveguide dual-passband electrically tunable filter provided by the invention.
Fig. 2 is the side view of a quarter structural substract integrated waveguide dual-passband electrically tunable filter provided by the invention.
Fig. 3 is the bottom substance schematic diagram of Fig. 1.
Fig. 4 be Fig. 1 in varactor apply bias voltage when return loss S11, insertion loss S21 curve and
The partial enlarged view of curve.
Wherein, 1 is medium substrate, and 21 cover steel structure for a quarter, and 22 be lower metal copper, and 23 is flat for large square metal
Face, 31 be the plated-through hole for constituting substrate integration wave-guide, and 32 be isolation plated-through hole, and 33 be ground metallization through-hole,
34 be center via hole, 41 be 50 ohm of input microstrip lines, 42 be 50 ohm of transition microstrip lines, 43 be 50 ohm of output microstrip lines, 5
It is complimentary square spiral resonant ring for L-type slot, 6,7 be metal right angled triangle, and 81 be the first L-type slot, and 82 be the second L-type slot,
83 be third L-type slot, and 84 be the 4th L-type slot, and 91 be the first notch, and 92 be the second notch, and 93 be third notch, and 94 cut for the 4th
Mouthful, 10 be undercut type perforated metal piece, and 11 be square metal piece, and 121 be the first rectangular metal pad, and 122 be the second rectangular gold
Belong to pad, 123 be third square metal pad, 124 be square metal pad, 125 be the 5th square metal pad, 126
For hexagon metal pad, 131 be the first rectangle perforated metal piece, and 132 be the first rectangle perforated metal piece, and 14 are limited galvanic electricity
Resistance, 15 be choke induction, and 16 be ground capacity, and 17 be capacitance, and 18 be varactor, and 19 be conventional capacitive, and 20 be straight
Galvanic electricity source.
Specific embodiment
Illustrate embodiments of the present invention below by way of specific specific example, those skilled in the art can be by this specification
Other advantages and efficacy of the present invention can be easily understood for disclosed content.The present invention can also pass through in addition different specific realities
The mode of applying is embodied or practiced, the various details in this specification can also based on different viewpoints and application, without departing from
Various modifications or alterations are carried out under spirit of the invention.
A kind of a quarter structural substract integrated waveguide dual-passband electrically tunable filter, including medium substrate 1, medium substrate
The a quarter of 1 upper surface covers the lower metal copper 22 of steel structure 21,1 lower surface of medium substrate;
The a quarter covers steel structure 21 and is equipped with the plated-through hole 31 for constituting substrate integration wave-guide, and a quarter is covered
21 lower left side of steel structure is the top of 41,50 ohm of 50 ohm of input microstrip lines input microstrip lines 41, constitutes substrate integration wave-guide
Plated-through hole 31 on the right side of be provided with L-type slot 5 and be used as co-planar waveguide input terminal;A quarter covers 21 inside L of steel structure
There is a complimentary square spiral resonant ring 6 on the right side of type groove 5;Covering on the right side of steel structure 21 in a quarter is 50 ohm of transition micro-strips
Line 42;A quarter covers the uniform plated-through hole 31 of a row of 21 edge side of steel structure through upper surface copper-clad, medium
Substrate, lower layer's copper-clad are uniformly metallized by upper layer copper-clad, medium substrate, lower layer's copper clad layers and one row of edge in this way
Through-hole 31 together forms a quarter and covers steel structure substrate integration wave-guide.
It is a large square metal flat 23,23 top of large square metal flat on the right side of 50 ohm of transition microstrip lines 42
Center connects 50 ohm of output microstrip lines, 43,50 ohm of about 42 two sides of transition microstrip line and is equipped with a pair of of L-type slot 81,82,50 Europe
Nurse, which exports, is equipped with a pair of of L-type slot 83,84 at left and right sides of microstrip line 43, four right angles of large square metal flat 23 are small just by four
It is rectangular to cut away, leave four notch 91,92,93,94;There is a undercut type perforated metal piece at 23 center of large square metal flat
10, center is equipped with center via hole 34, and a square metal piece 11, the punching of undercut type are equipped with below undercut type perforated metal piece 10
Conventional capacitive 19 is welded between sheet metal 10 and square metal piece 11;
It is biasing circuit that a quarter, which is covered below steel structure 21 and 50 ohm input microstrip line 41, comprising: six sides
Shape metal pad 121-126 welds current limiting electricity between the first rectangular metal pad 121 and the second rectangular metal pad 122
Resistance 14, is welded with choke induction 15 between the second rectangular metal pad 122 and third square metal pad 123, rectangular second
It is welded with ground capacity 16 between metal pad 122 and square metal pad 124, in 123 He of third square metal pad
It is welded with capacitance 17 between 5th square metal pad 125, in third square metal pad 123 and hexagon metal welding
Varactor 18 is welded between disk 126, the part under hexagon metal pad 126 and the first rectangular metal pad 121
Not She You the first rectangle perforated metal piece 131, the second rectangle perforated metal piece 132, the first rectangle perforated metal piece 131, second
Rectangle perforated metal piece 132 is equipped with ground metallization through-hole 33, the first rectangular metal pad 121 and the second rectangle perforated metal
It is DC power supply 20 between piece 132, DC power supply 20 is biased by the circuit by the first rectangular metal pad 121
Two rectangle perforated metal pieces 132 are grounded, and hexagon metal pad 126 is connected with the first rectangle perforated metal piece 131
For being grounded;
5th square metal pad 125 connection a quarter is covered in the complimentary square spiral resonant ring 6 in steel structure 21
The heart and conventional capacitive 19, connect third square metal pad 123 by capacitance 17 below, and a quarter covers steel structure 21
And below large square metal flat 23 between the biasing circuit by parallel isolation plated-through hole 32 carry out every
From.
The junction that a quarter covers steel structure 21 and 50 ohm transition microstrip line 42 is equipped with a metal right angled triangle
7, in order to reduce reflection.
First rectangular metal pad 121, the second rectangular metal pad 122, third square metal pad 123, hexagon
Metal pad 126 is located in same horizontal line, and the 5th square metal pad 125 is located at 123 top of third square metal pad, the
Square metal pad 124 is located at the second rectangular 122 lower section of metal pad.
The complimentary square spiral resonant ring 6 includes inner ring and outer rings, and wherein inner ring connects with outer ring, two resonant rings
Width and spacing are equal.
In the present embodiment, medium substrate uses Rogers 4350, dielectric constant 3.66, fissipation factor 0.004, thickness
Degree is 0.508mm, and varactor is sealed using the SMV1405 series varactor of skyworks company using SC-79
The PIN diode total length of dress, this encapsulation is about 1.5mm to 1.7mm, and the length of pin is about 0.15mm, and choke induction is
8nH, capacitance 100pF, current-limiting resistance are 200 ohm, ground capacity 1000pF, conventional capacitive 0.4pF, chokes electricity
Sense, capacitance, current-limiting resistance, ground capacity, conventional capacitive are all made of 0402 encapsulation, i.e., inductance and capacitance resistance equal length and
Width is 1mm and 0.5mm, and a quarter covers steel structure downside, and there are six square metal pads, and length of bonding pad and width are all set as
1mm, in addition to being divided into 1.3mm between third square metal pad 123 and hexagon metal pad 126, remaining pad it
Between between be divided into 0.635mm.The external sub-miniature A connector of 50 ohm microstrips and being connected on vector network analyzer measures, and works as voltage
When changing between 3V to 30V, the first passband central frequency changes to 1.586GHz from 1.349GHz, and tuning range is
237MHz, insertion loss changes to 0.584dB by 1.422dB, and the second passband central frequency is 7.991GHz and protects always
Hold constant, entire circuit size is that a length of 24mm wide is 27mm.
The present invention uses substrate integrated waveguide technology, and compared to microstrip line, its Q value is high, light-weight, and small, power appearance is lost
Amount is big, at low cost, is easy to integrated with other planar circuits.It is substrate integration wave-guide that a quarter, which covers steel structure substrate integration wave-guide,
Along central cross and a quarter structure obtained from longitudinal cut away, structure is greatly reduced, and has the function of miniaturization.
Due to using the relationship of substrate integrated waveguide technology, equivalent dimension and resonance frequency by substrate integration wave-guide can
To know, resonance frequency is smaller, and size is bigger, so be very unlikely to realize using the low-frequency filter of substrate integrated waveguide technology, this
Inventing an advantage is using complement helical resonant ring, so that resonance frequency strongly reduces, therefore by complement helical resonant ring control
Its resonance frequency is made, so that the size of external a quarter structural substract integrated waveguide greatly reduces.
The present invention covers steel structure substrate integration wave-guide by a quarter and complimentary square spiral resonant ring generates the first passband,
And have a transmission zero, and respectively have a pair of of L-type slot by 50 ohm of transition, output microstrip line both sides, the effect of this four L-type slots
It is that perturbation is formed to the current distribution of filter, has motivated bimodulus, generated the second passband, and had good harmonics restraint to act on,
It is in order to reduce impedance, so that resonance frequency reduces that four right angles of large square metal flat are cut away by four small squares.
The present invention has a undercut type perforated metal piece and center via hole at large square metal flat center, beats in undercut type
One square metal piece is arranged at mesoporous metal piece lower part, is that an electricity will be welded between undercut type perforated metal piece and square metal piece here
Hold, it is therefore an objective under applying bias voltage effect, inhibit higher hamonic wave effect.
The present invention is transitioned into resonant cavity using L-type coplanar waveguide form after 50 ohm microstrips, can be significantly reduced
Reflection;A quarter, which is covered on the downside of steel structure, has a row along the metallization VIA of parallelism structural, and the purpose is to reduce pad and four points
One of cover the coupling between steel structure and large square metal flat and influence the performance of filter;Voltage passes through base in order to prevent
Piece integrated waveguide enters vector network analyzer and damages, and also choke induction, choke induction are welded between pad
It is in order to every the logical direct current of exchange.
The present invention can improve the radius of complement helical resonant ring, the length and width of four L-type slots, control and requiring
The passband for making different frequency ranges, has a wide range of applications market.The filter has small in size, and insertion loss is low, centre frequency
The features such as continuously adjustable, Out-of-band rejection height, load DC feedback are conveniently, tuned speed is fast, tuning facilitates.
The above-described embodiments merely illustrate the principles and effects of the present invention, and is not intended to limit the present invention.It is any ripe
The personage for knowing this technology all without departing from the spirit and scope of the present invention, carries out modifications and changes to above-described embodiment.Cause
This, all those of ordinary skill in the art are completed without departing from the spirit and technical ideas disclosed in the present invention
All equivalent modifications or change, should be covered by the claims of the present invention.