CN203288723U

CN203288723U - Interdigital coupling diplexer

Info

Publication number: CN203288723U
Application number: CN2013201417569U
Authority: CN
Inventors: 王世伟; 刘晓晗; 陈瑞森; 汪凯; 郑丽昇; 褚庆昕
Original assignee: South China University of Technology SCUT
Current assignee: South China University of Technology SCUT
Priority date: 2013-03-26
Filing date: 2013-03-26
Publication date: 2013-11-13
Anticipated expiration: 2023-03-26

Abstract

The utility model discloses an interdigital coupling diplexer comprising a substrate, a bottom surface of which is covered by a metal floor layer. A front surface of the substrate comprises two pairs of coupling wires, which are in an upper-lower arrangement, are provided with the same structure and aligned end parts; and matched lines, which are respectively disposed on central parts of the two ends of the upper pair of coupling wires and the lower pair of coupling wires. Each of the pairs of coupling wires is provided with a centrosymmetric short circuit branch structure, which is connected with the metal floor layer of the bottom surface of the substrate. The lengths of the matched lines on the two ends of each of the pairs of coupling wires are equal to the coupling length of the coupling wires. The interdigital coupling diplexer is advantageous in that the transmission zero point can be generated by additionally providing the short circuit branch, and the band width of the diplexer can be adjusted by changing the position of the short circuit branch, and therefore the requirements of the special band width of the communication system can be satisfied, the interdigital coupling structure can be formed by the above mentioned coupling, the out-band attenuation can be improved, and the better filtering performance can be provided; the technical scheme is convenient and easy to realize, the size is small, the cost is low, the feature is good, and the diplexer is suitable for various communication systems.

Description

A kind of interdigital coupling duplexer

Technical field

The utility model relates to microstrip line form duplexer, relates in particular to a kind of interdigital coupling duplexer.

Background technology

Along with the fast development of radio communication, the frequency resource growing tension, as the important part of wireless communication system, the performance quality of duplexer directly has influence on the quality of communication system.

Duplexer commonly used in the communications field has:

1, waveguide duplexer: the time of this duplexer application is also the most ripe at most, and its loss is low, and operating frequency is high, but volume is large, cost is high, tuning difficulty;

2, coaxial duplexer: as medium and the silver-plated coaxial duplexer of internal and external conductor, its dielectric loss and ohmic loss are all very little, and stability is high, shielding is good with air, but in the mobile communication frequency domain, it is too large that its volume still seems;

3, dielectric duplexer: it has realized the miniaturization of duplexer, but because cost is too high, so be not widely used in the communications field;

4, SAW duplexer: this duplexer is due to the frequency characteristic that can realize arbitrary accuracy, and volume is little, design flexibility is good, high reliability, be widely used in the communications field, its weak point is that cost is high, and insertion loss is large, and it is low that high frequency bears power, so be suitable for the exigent mobile communication terminal of miniaturization.

Summary of the invention

The purpose of this utility model is to overcome the shortcoming and defect of above-mentioned prior art, and a kind of interdigital coupling duplexer is provided, and overcomes the poor difficulty of existing micro-strip duplexer filtering characteristic, and has solved the problem that passband can't independently be controlled.

The utility model is achieved through the following technical solutions:

A kind of interdigital coupling duplexer, comprise substrate, and the bottom surface of substrate is covered by the metal stratum, and substrate front side comprises the two pairs of coupling lines that structure is identical and end flushes in up and down, and the matched line that is separately positioned on the two pairs of coupling line two ends central authorities in up and down; Every a pair of coupling line all has centrosymmetric short branch, and short branch is connected with the metal stratum of substrate bottom surface; The matched line at every a pair of coupling line two ends equates with this coupling length to coupling line.

The length of the two pairs of coupling lines in up and down can be different, perhaps go up the length of the length of coupling line greater than lower coupling line.

The coupling length of upper coupling line two ends matched line is greater than the coupling length of lower coupling line two ends matched line.

The matched line of the two pairs of mutually same ends of coupling line in up and down shares connectivity port one, and the matched line of the two pairs of coupling line other ends in up and down is connectivity port two and port three respectively.

, in the central authorities of port one matching connection line one end, also have additional rectangle coupling detail.

The utility model, with respect to prior art, has following advantage and effect:

By increasing short branch (virtual earth), produce transmission zero, can adjust by the position that changes short branch the bandwidth of duplexer, to meet in communication system the needs to specific bandwidth.

The matched line at every a pair of coupling line two ends equates with this coupling length to coupling line, and this coupling has formed interdigital coupled structure, has improved attenuation outside a channel, has better filtering characteristic.

The utility model technological means is simple and easy to do, and volume is little, and cost is low, and characteristic is good, is applicable to plurality of communication systems.

Description of drawings

Fig. 1 is the interdigital coupling diplexer structure of the utility model schematic diagram.

Fig. 2 is port one and the transmission coefficient of port two and the reflection coefficient of port two (unit: decibel).

Fig. 3 be port one to port three transmission coefficient and the reflection coefficient (unit: decibel) of port three.

Fig. 4 be port three with port two isolation and the reflection coefficient (unit: decibel) of port one.

In Fig. 2～Fig. 4, solid line represents Simulation, and dotted line represents Measurement.

Embodiment

Below in conjunction with specific embodiment, the utility model is more specifically described in detail.

Embodiment

As shown in Figure 1, the interdigital coupling duplexer of the utility model, comprise substrate 9, the bottom surface of substrate 9 covers (not shown) by the metal stratum, substrate 9 fronts comprise two pairs of the up and down coupling line that structure is identical and

end flushes

4,5, and the matched line 6 that is separately positioned on two pairs of up and down

coupling line

4,5 two ends central authorities; Every a pair of coupling line all has centrosymmetric short branch 7, and short branch 7 is connected with the metal stratum of substrate 9 bottom surfaces; The matched line 6 at every a pair of coupling line two ends equates with this coupling length to coupling line, but the coupling length of upper coupling line 4 two ends matched lines 6 is greater than the coupling length of lower coupling line 5 two ends matched lines 6.

In practical application, the two pairs of coupling lines 4 in up and down, 5 length can be different, and the length of the upper coupling line that this implementation column provides is greater than the length of lower coupling line.

The matched line 6 of two pairs of up and down

coupling line

4,5 mutually same ends shares connectivity port 1, and the matched line 6 of two pairs of up and down

coupling line

4,5 other ends is connectivity port 22 and port 33 respectively.

, in the central authorities of port one 1 matching connection line 6 one ends, also have additional rectangle coupling detail 8.

The two pairs of

coupling lines

4,5 that structure is identical in up and down, in fact formed two rotational symmetric band pass filters, and every pair of coupling line all has centrosymmetric short branch 7(and is equivalent to virtual earth) be used for producing transmission zero, adjust bandwidth;

And the matched line 6 at every a pair of

coupling line

4,5 two ends forms interdigital coupling, is used for improving attenuation outside a channel, improves filtering characteristic; Port 1, port 22 and port 33 adopt 50 ohm microstrip to be used for doing feeder line.

, by adjusting two pairs of up and down

coupling line

4,5 length, width, spacing, and adjust matched line 6 and the coupling length between the two pairs of

coupling lines

4,5 up and down etc. in practical application, the passband of higher (perhaps lower) frequency is moved.

The utility model structure as shown in Figure 1, have good attenuation outside a channel characteristic, and insertion loss is little, and volume is little, in actual applications, uses convenient.

Fig. 2 shows port 1 and the transmission coefficient of port 22 and the reflection coefficient of port 22 (unit: decibel) curve chart.

Fig. 3 show port 1 to port 33 transmission coefficient and the reflection coefficient (unit: decibel) curve chart of port 33.

Fig. 4 show port 33 and port 22 isolation and the reflection coefficient (unit: decibel) curve chart of port 1.

As mentioned above, just can realize preferably the utility model.

Execution mode of the present utility model is not restricted to the described embodiments; other are any does not deviate from change, the modification done under the Spirit Essence of this utility model and principle, substitute, combination, simplify; all should be the substitute mode of equivalence, within being included in protection range of the present utility model.

Claims

1. interdigital coupling duplexer, comprise substrate, the bottom surface of substrate is covered by the metal stratum, it is characterized in that: substrate front side comprises the two pairs of coupling lines that structure is identical and end flushes in up and down, and the matched line that is separately positioned on the two pairs of coupling line two ends central authorities in up and down; Every a pair of coupling line all has centrosymmetric short branch, and short branch is connected with the metal stratum of substrate bottom surface; The matched line at every a pair of coupling line two ends equates with this coupling length to coupling line.

2. interdigital coupling duplexer according to claim 1, is characterized in that: the length difference of the two pairs of coupling lines in up and down.

3. interdigital coupling duplexer according to claim 1, is characterized in that: go up the length of the length of coupling line greater than lower coupling line.

4. the described interdigital coupling duplexer of any one according to claim 1～3, it is characterized in that: the coupling length of upper coupling line two ends matched line is greater than the coupling length of lower coupling line two ends matched line.

5. interdigital coupling duplexer according to claim 4, is characterized in that: the shared connectivity port one of the matched line of the two pairs of mutually same ends of coupling line in up and down, matched line difference connectivity port two and the port three of the two pairs of coupling line other ends in up and down.

6. interdigital coupling duplexer according to claim 5, is characterized in that:, in the central authorities of port one matching connection line one end, also have additional rectangle coupling detail.