The antenna tuning network structure and method of impedance matching are realized for shortwave loop antenna
Technical field
The invention belongs to electronic circuit design field, and in particular to a kind of day that impedance matching is realized for shortwave loop antenna
Adjust network structure and method.
Background technology
Short wave communication frequency range is wider (1.6MHz-30MHz), and the input impedance of narrow-band antenna changes with frequency, is one multiple
Impedance, and the output impedance of general emitter is 50 Ω, so needing in the root of antenna, i.e., to concatenate between antenna and emitter
Antenna tuner (hereinafter referred to as day tune) realizes the impedance matching of each Frequency point between the two, makes the power of emitter to greatest extent
Transmit to antenna.
Loop antenna is also known as resonance loop antenna, magnetic loop antenna, electric current loop antenna etc., is a kind of short-wave antenna of high elevation radiation
(the similar end of double annulus, the straight-flanked ring shown in accompanying drawing 2 etc. as shown in Figure 1 is grounded or formed semi-ring, the shape of polygon
Formula), it is mainly used in the occasion of the short wave communication such as bearing, be vehicle-mounted, be airborne of limited space.
Loop antenna typically realizes the transmitting of antenna by being connected to the tunable capacitor of big ring end (by motor or manual)
Impedance matching between machine, for adjustable extent typically in 3-12MHz, and tuning precision is relatively low, standing-wave ratio is less than 2.5.And shortwave is remote
During distance communication, can passband rate it is higher (more than 12MHz), so loop antenna is difficult to meet telecommunication use demand.
The content of the invention
To solve the above problems, the present invention one kind is disclosed can be by shortwave loop antenna in full frequency band (1.6-30MHz) impedance
The antenna tuning network structure and method of matching, to extend the operating frequency range of the impedance matching scope of day tune and shortwave loop antenna,
The precision of its tuning is improved, loss of the power on day tune is reduced, improves short wave communication distance.Concrete scheme is as follows:
The present invention discloses a kind of antenna tuning network structure that impedance matching is realized for shortwave loop antenna, it is characterised in that:Bag
Include the front end matching network of the rf inputs positioned at small ring and the end matching network positioned at big ring end;Front end matching network
Using the adjustable matching networks of LC, LC is adjustable matching network by one group of series connection controllable impedance and one group of tunable capacitor group in parallel
Into;End matching network is made up of the tunable capacitor of one group of variable in-line or parallel connection.
As a kind of preferred scheme, controllable impedance is made up of the discrete inductance of multiple values discrete in a binary fashion, can
Electric capacity is adjusted to be made up of the discrete capacitor of discrete value in a binary fashion;Each discrete inductance or discrete capacitor are each equipped with and controlled
System electrically connects and is used to control it accesses the network whether controlling switch.
As a kind of preferred scheme, controlling switch is to be connected in parallel on each discrete inductance both ends or be connected in each discrete capacitor
Relay.
The present invention discloses also a kind of method for realizing impedance matching for shortwave loop antenna, increases in the rf inputs of small ring
Add one group of front end matching network, increase by a group end matching network in big ring end;Front end matching network uses the adjustable matchings of LC
Network, LC is adjustable matching network are made up of the controllable impedance and one group of tunable capacitor in parallel of one group of series connection;End matching network
It is made up of the tunable capacitor of one group of variable in-line or parallel connection;
In default low-frequency range, using the adjustable series electric capacity of big ring end as master network, the LC of small ring front end is adjustable
Matching network is as secondary network;In default high band, master network, big ring are used as using the adjustable matching networks of LC of small ring front end
The adjustable shunt capacitance of end is as secondary network, so as to realize quick impedance matching.
As a kind of preferred scheme, controllable impedance is made up of the discrete inductance of multiple values discrete in a binary fashion, can
Electric capacity is adjusted to be made up of the discrete capacitor of discrete value in a binary fashion;Each discrete inductance or discrete capacitor are each equipped with and controlled
System electrically connects and is used to control it accesses the network whether controlling switch.
As a kind of preferred scheme, default low, high band boundary frequency value is matched by the ring size of antenna and end
Adjustable series electric capacity in network can the precision of value determine.
As a kind of preferred scheme, front end matching network is located at antenna rf input, passes through end matching network or straight
Connect and be connected with emitter;End matching network is connected to end or the earth terminal of loop aerial.
As a kind of preferred scheme, end matching network is integrated in the matching network of front end, is cooperateed with front end matching network
Work, as the supplement of front end matching network, the matching range of expansion front end matching network.
As a kind of preferred scheme, controlling switch is to be connected in parallel on each discrete inductance both ends or be connected in each discrete capacitor
Relay.
As a kind of preferred scheme, in low-frequency range, each controlling switch is first passed through to the adjustable series electricity as master network
Appearance is adjusted, and ensures that standing-wave ratio is less than 3, then the adjustable matching networks of LC for being used as secondary network are adjusted by each controlling switch
Section, ensure that standing-wave ratio is less than 1.5;In high band, each controlling switch of control is first passed through to the adjustable matchings of LC as master network
Network is adjusted, and ensures that standing-wave ratio is less than 3, then by controlling each controlling switch to enter the adjustable shunt capacitance for being used as secondary network
Row regulation, ensure that standing-wave ratio is less than 1.5.
Beneficial effect:
Present invention can apply to bear, on the vehicle-mounted or relatively limited carrier in space such as airborne, shortwave ring day can be extended
The operating frequency range of line, reduces loss of the power inside day tune, and automatic and be rapidly completed impedance matching, improves shortwave ring
The radiation efficiency and communication distance of antenna.
Brief description of the drawings
The double circular loop antenna schematic diagrames of Fig. 1;
Fig. 2 rectangle loop antenna schematic diagrames;
Fig. 3 shortwave loop antenna matching network structural representations;
Fig. 4 front ends matching network circuit schematic diagram;
Fig. 5 ends matching network circuit schematic diagram;
Fig. 6 front ends matching network and end matching network associated working circuit diagram;
Fig. 7 front ends and end matching network are installed separately schematic diagram:(a) double form of annular rings;(b) double form of annular rings;Rectangle
Loop type;
Fig. 8 front ends and end the matching network connection diagram in a structure:(a) double form of annular rings;(b) straight-flanked ring
Form.
Specific embodiment
As shown in figure 3, embodiment 1 provides a kind of matching network structural representation, traditional matching network is divided into two
Point, a part is located at the front end (i.e. rf inputs) of small ring, referred to as front end matching network;Another part is located at the end of big ring
End, referred to as end matching network.
As shown in figure 4, front end matching network is using the adjustable matching networks of LC, LC is adjustable matching network is mainly by one group
The tunable capacitor in parallel of the controllable impedance (i.e. L11, L12 ..., L1N in Fig. 4) of series connection and one group (i.e. C11 in Fig. 4,
C12 ..., C1N) composition, controllable impedance or tunable capacitor be by multiple values discrete in a binary fashion discrete series inductance or
The discrete shunt capacitance composition of multiple values discrete in a binary fashion, each discrete inductance or discrete capacitor are equipped with one
Individual corresponding relay, each relay electrically connect with control system, for controlling whether corresponding discrete inductance or electric capacity connect
Enter the network.
As shown in figure 5, end matching network is mainly made up of the tunable capacitor of one group of variable in-line or parallel connection, tunable capacitor
It is made up of the discrete capacitor of multiple values discrete in a binary fashion, each discrete capacitor has a corresponding relay,
Each relay electrically connects with control system, controls whether corresponding discrete capacitor device accesses the network.
More than design in, in front end matching network and end matching network each group discrete device quantity selection with inductance or
The span of electric capacity is related, i.e. highest and minimum span, for example, discrete inductance can take 0.1uH, 0.2uH,
0.4uH, 0.8uH, 1.6uH, 3.2uH, 6.4uH, 12.8uH, 25.6uH, then the minimum inductance value after its combination is 0.1uH, most
High inductance value is 51.1uH, and value precision is 0.1uH.
When physical circuit designs, front end matching network and end matching network may be designed to two separate moulds
Block, and be connected respectively with small ring, big ring.As shown in fig. 7, front end matching network is located at antenna rf input, it passes through end
Matching network is connected with emitter, directly can also be connected with emitter.As shown in Fig. 7 (a), in double circular loop antenna loops,
End matching network is located at double circular loop antenna loop ends, and the connecting line of front end matching network and end matching network includes electricity
Source/control/radio frequency;As shown in Fig. 7 (b), in straight-flanked ring antenna loop, end matching network is located at square with traditional day tone category seemingly
The connecting line of the earth terminal of shape loop antenna, front end matching network and end matching network includes power supply/control, not including radio frequency.
It can specifically be selected to be connected to antenna end or earth terminal according to the characteristics of antenna structure.Front end matching network and end matching network
Controlled, cooperated by control system simultaneously.The design of this standalone module is highly suitable for the limited situation of installing space, just
Installed in using limited space.
This two parts network can be also concentrated in a structure.As shown in figure 8, front end matching network and end pair net
Network is designed in an overall network structure, and is connected as an entirety with antenna.In specific design, end matching network
Matching network that can be independent as one, is only integrated in front network in a hardware configuration body, but functionally still
Independently of each other;Front end matching network and end matching network can also be got in touch with, functionally mutually utilized, such as can be by end
Matching network is integrated in the matching network of front end, can be designed to cooperate end matching network with front end matching network, be made
For the supplement of front end matching network, so as to expand the matching range of front end matching network.As shown in fig. 6, in embodiment, will can scheme
End matching network circuit in 5 is connected serially between front end matching network and the antenna in Fig. 4, and one as front end matching network
Part, extend impedance matching scope.This annexation is relatively simple, adjusts difference little with traditional day, installation is simple and convenient.
With reference to shown in Fig. 3, C1n (tunable capacitor C11, C12 ..., C1N in corresponding diagram 4), L1n is (adjustable in corresponding diagram 4
Inductance L11, L12 ..., L1N), the controllable impedance in C2n (tunable capacitor C21, C22 ..., C2N in corresponding diagram 5) or adjustable electric
Appearance is made up of the discrete inductance or discrete capacitor of multiple values discrete in a binary fashion respectively, each discrete inductance or discrete capacitor
Connect relay K1n (relay K11, K12 ..., K1N in corresponding diagram 4), the K2n (relays in corresponding diagram 4 of control system
K21, K22 ..., K2N), K3n (relay K31, K32 ..., K3N in corresponding diagram 5) is to each discrete inductance or electric capacity on network
Whether it is linked into network to be controlled, by way of control system control relay acts, so as to realize quickly selection
The value of inductance or electric capacity in distribution network.
Default low-frequency range of the present invention and the boundary frequency value of high band are can by the size and end of antenna loop
Adjust series capacitance can value precision determine, general antenna ring size is bigger, and boundary frequency value is lower;End adjustable series electric capacity
Can value precision it is lower, boundary frequency value is also lower.Using 12MHz as boundary frequency value in embodiment, i.e. low-frequency range refers to 2-
12MHz;High band refers to 12MHz-30MHz.
Concrete operating principle is as follows:
At default low-frequency range (such as 1.6-12MHz), the impedance operator of loop antenna is in perception, mainly with end pair net
Network is master network, and whether the access of each electric capacity to be in control system control end matching network, is accessed by the combination of different electric capacity,
Ensure that the standing-wave ratio after matching can reach within 3;Then again using front end matching network as secondary network, before being controlled by control system
Hold matching network in each inductance, electric capacity access whether, improve tuning precision, standing-wave ratio is down to less inductance capacitance value
Within 1.5.By the regulation process of first coarse adjustment accurate adjustment again, ensure the good result of impedance matching.
At default high band (such as 12-30MHz), the impedance operator of loop antenna is in capacitive, mainly with front end matching network
For master network, using end matching network as secondary network.Similarly, first pass through control system control front end matching network in each inductance,
Whether electric capacity accesses the coarse adjustment for carrying out standing-wave ratio, then controls whether the access of each inductance in the matching network of end, electric capacity is carried out
The fine setting of standing-wave ratio, so as to realize quick impedance matching.
Although embodiment of the present invention is described above in association with accompanying drawing, the invention is not limited in above-mentioned
Specific embodiments and applications field, above-mentioned specific embodiment are only schematical, directiveness, rather than restricted
's.One of ordinary skill in the art is under the enlightenment of this specification, in the scope for not departing from the claims in the present invention and being protected
In the case of, the form of many kinds can also be made, these belong to the row of protection of the invention.