CN108832237B

CN108832237B - Dual-band reconfigurable filter based on SIR loading PIN diode structure

Info

Publication number: CN108832237B
Application number: CN201810433580.1A
Authority: CN
Inventors: 肖泽龙; 许辉达; 许建中; 吴礼; 王静; 高晓堃; 张晋宇
Original assignee: Nanjing University of Science and Technology
Current assignee: Nanjing University of Science and Technology
Priority date: 2018-05-08
Filing date: 2018-05-08
Publication date: 2021-06-29
Anticipated expiration: 2038-05-08
Also published as: CN108832237A

Abstract

The invention provides a double-frequency-band reconfigurable filter based on an SIR loading PIN diode structure, which comprises a dielectric substrate, a printed microstrip line circuit on the dielectric substrate, and a metal copper clad arranged under the dielectric substrate, wherein the metal copper clad is grounded; the upper microstrip line circuit comprises three U-shaped SIR resonators and signal coupling lines, wherein the first SIR resonator is positioned above the coupling lines, and the second SIR resonator and the third SIR resonator are symmetrically distributed below the signal coupling lines. A PIN diode is loaded on the resonator and connected with a matched load or an impedance line, and the reconfigurable function of the filter is realized by regulating and controlling the PIN switch diode. The double-frequency-band reconfigurable filter based on the SIR loaded PIN diode structure has the characteristics of large pass band frequency hopping range, compact structure, low stray frequency, large mutual isolation of two frequency bands and the like.

Description

Dual-band reconfigurable filter based on SIR loading PIN diode structure

Technical Field

The invention relates to the technical field of reconfigurable filters, in particular to a dual-band reconfigurable filter based on an SIR loading PIN diode structure.

Background

With the rapid development of electronic countermeasure, in order to improve the anti-interference capability of a fuze system, the modern fuze technology develops towards the trend of multi-band and multi-system. In different working frequency bands and working modes, the transceiving front end of the transceiving front end needs to adopt a filter bank consisting of a plurality of different central frequencies to select the frequency. The filter bank has the defects that the system framework becomes complicated, the system size is increased, obvious loss is brought, and the mainstream trend of miniaturization, integration and low energy consumption of the current transceiving front-end circuit is not met. Therefore, it is desirable to use one filter to implement the functions of multiple filters, and this drawback can be well compensated by using the radio frequency reconfigurable technology. However, most of the reconfigurable filter researches reported at present adopt a method of loading tunable capacitors, so that the frequency tuning within L, S wave bands in a small range is realized, and the requirements of multi-band and multi-body fuse systems can not be met.

Disclosure of Invention

The invention aims to provide a dual-band reconfigurable filter based on an SIR loading PIN diode structure, aiming at overcoming the defects of the background technology and meeting the requirement of a radio frequency front end on large-range frequency switching.

The technical solution for realizing the invention is as follows: a dual-band reconfigurable filter based on an SIR loaded PIN diode structure comprises a dielectric substrate, a printed microstrip line circuit on the dielectric substrate, and a copper clad arranged below the dielectric substrate, wherein the copper clad is grounded; the microstrip line circuit comprises a first SIR resonator, a second SIR resonator, a third SIR resonator, a signal coupling line, an impedance matching line and a filter output end, wherein the first resonator is a U-shaped resonator with a symmetrical structure and comprises two arms of the U-shaped resonator and a beam of the U-shaped resonator; the SIR resonator II and the SIR resonator III are completely the same and are U-shaped resonators with asymmetric structures, the SIR resonator II and the SIR resonator III are positioned on the outer side of the U-shaped resonator beam and are symmetrical with respect to the center line of the SIR resonator I; the signal coupling line is arranged along a gap between the U-shaped resonator beam and the SIR resonator II and the SIR resonator III, two ends of the signal coupling line are respectively connected with one end of an impedance matching line, and the other end of the impedance matching line is connected with the output end of the filter.

Compared with the prior art, the invention has the following remarkable advantages:

(1) compared with some current reconfigurable filters, the passband frequency hopping range is large.

(2) The structure of separating the resonators of the lower passband and the upper passband of the filter is adopted, and the two passbands of the filter

The center frequency, bandwidth and in-band characteristics of the antenna can be independently adjusted.

(3) Use of SIR resonator technology to make the overall structure more compact and reduce resonator generation undesirable

The existing spurious frequencies.

(4) Based on the ingenious design of the coupling structure, the two-way band is used for regulating and controlling the switching frequency of the PIN switch diode

The mutual influence of (a) is very small.

The present invention is described in further detail below with reference to the attached drawings.

Drawings

Fig. 1 is a schematic view of a printed circuit board employed in the present invention.

Fig. 2 is a schematic top view of a microstrip line circuit of the present invention.

FIG. 3 is a schematic diagram of simulation of dual passband setup S parameters according to the present invention, using joint simulation of HFSS and ADS.

FIG. 4 is a schematic diagram of S parameter simulation for lower passband on and upper passband off according to the present invention, using joint simulation of HFSS and ADS.

FIG. 5 is a schematic diagram of S parameter simulation for lower passband closing and upper passband opening according to the present invention, using joint simulation of HFSS and ADS.

Fig. 6 is a schematic diagram of simulation of dual-passband shutdown S parameters according to the present invention, which employs joint simulation of HFSS and ADS.

Detailed Description

The invention discloses a double-frequency-band reconfigurable filter based on an SIR loading PIN diode structure, which comprises a dielectric substrate 1, a printed microstrip line circuit 2 on the dielectric substrate 1, and a metal copper clad 3 arranged below the dielectric substrate 1, wherein the metal copper clad 3 is grounded; the microstrip line circuit 2 comprises a first SIR resonator 21, a second SIR resonator 22, a third SIR resonator 23, a signal coupling line 24, an impedance matching line 25 and a filter output end 26, wherein the first SIR resonator 21 is a symmetrical U-shaped resonator and comprises a U-shaped resonator double arm 211 and a U-shaped resonator beam 212; the SIR resonator II 22 and the SIR resonator III 23 are completely identical and are U-shaped resonators with asymmetric structures, the SIR resonator II 22 and the SIR resonator III 23 are located on the outer side of the U-shaped resonator beam 212, and the SIR resonator II 22 and the SIR resonator III 23 are symmetrical about the center line of the resonator I21; the signal coupling line 24 is arranged along the gap between the U-shaped resonator beam 212 and the SIR resonator two 22 and the SIR resonator three 23, two ends of the signal coupling line 24 are respectively connected with one end of the impedance matching line 25, and the other end of the impedance matching line 25 is connected with the filter output end 26.

In a further embodiment, the two arms 211 of the U-shaped resonator have open ports, the U-shaped resonator beam 212 is a high impedance line, and two ends of the U-shaped resonator beam 212 are respectively connected to a segment of coupling extension line 213 along the extending direction thereof.

In a further embodiment, the length of the coupling extension line 213 is 2.6mm

In a further embodiment, the second SIR resonator 22 includes a U-shaped resonator left arm 221, a U-shaped resonator right arm 222, and a U-shaped resonator beam 223, where the U-shaped resonator beam 223 is a high impedance line, and ports of the U-shaped resonator left arm 221 and the U-shaped resonator right arm 222 are set to be open circuits.

Preferably, the U-shaped resonator right arm 222 of the SIR resonator two 22 is connected to a PIN diode three 283, and the other end of the PIN diode three 283 is connected to the terminal open line 263; the U-shaped resonator left arm 232 of SIR resonator three 23 is connected to PIN diode four 284, the other end of PIN diode four 284 is connected to impedance line two 262, and the other end of impedance line two 262 is connected to matched load two 272.

Preferably, the open-ended line 263 is a quarter wavelength line, the characteristic impedance of the second impedance line 262 is 50 ohms, and the impedance of the second matching load 272 is 50 ohms.

In a further embodiment, the ports of the U-shaped resonator double arm 211 are respectively connected with one end of a PIN diode 281, the other end of the PIN diode 281 is connected with one end of an impedance line 261, and the other end of the impedance line 261 is connected with a matched load one 271.

Preferably, the characteristic impedance of the first impedance line 261 is 50 ohms, and the impedance of the first matched load 271 is 50 ohms.

Preferably, the coupling distance between the first SIR resonator 21 and the signal coupling line 24 is the same as the coupling distance between the second SIR resonator 22 and the third SIR resonator 23 and the signal coupling line 24.

Preferably, the signal coupling line 24 includes a left signal coupling line 241 and a right signal coupling line 242, and the left signal coupling line 241 and the right signal coupling line 242 are symmetrical about a center line of the first resonator 21.

The present invention will be further described with reference to the following examples.

Example 1

As shown in fig. 1, the dual-band reconfigurable filter based on the SIR-loaded PIN diode structure of the present embodiment includes a dielectric substrate, where a Rogers4350 substrate may be used, the relative dielectric constant of which is 3.66 and the thickness of which is 1.524mm, and substrates of other specifications may also be used. The dielectric substrate is printed with a microstrip line circuit, the microstrip line circuit is made of a material with good conductivity, the material is copper with the thickness of 1 ounce, and a gold plating process is adopted. And the metal copper plating below the dielectric substrate is used as the ground of the whole filter.

As shown in fig. 2, the microstrip circuit includes three U-shaped SIR resonators, two signal coupling lines, an impedance matching line, four PIN switching diodes, an open terminal line, three impedance lines, and three matching loads. The SIR resonator is a symmetrical U-shaped structure and is positioned above the right middle of the signal coupling line, and the coupling distance is 0.2 mm; the length of the two arms of the U resonator is 3.8mm, and the width of the two arms of the U resonator is 4.16 mm; the length of the beam of the U resonator is 8mm, and the width of the beam of the U resonator is 1.1 mm; similarly, the length of the two coupling extension lines is 2.6mm, and the width is 1.1 mm. The SIR resonator II and the SIR resonator III are symmetrically distributed about the Y axis, are in asymmetric U-shaped structures and are positioned below the signal coupling line, and the coupling distance is 0.2 mm; the left arm of the U-shaped resonator is 3.6mm in length and 1.9mm in width; the length of the right arm of the U-shaped resonator is 3.6mm, and the width of the right arm of the U-shaped resonator is 1.26 mm; the beam length of the U-shaped resonator is 3.7mm, and the width of the U-shaped resonator is 0.86 mm. The two sections of signal coupling lines are symmetrically distributed about an axis Y, the coupling distance is 0.9mm, the length is 13.5mm, and the width is 1.1 mm. The impedance matching line is connected with the signal coupling line, in order to reduce the size of the filter, the impedance matching line is turned towards the Y-axis direction, a corner is further cut, reflection is reduced, and therefore matching is better adjusted, the length of the impedance matching line is 19mm, and the width of the impedance matching line is 1.5 mm.

And the open end of the two arms of the U resonator of the SIR resonator I is connected with a PIN diode I and a switch diode II, and the other end of the PIN switch diode is connected with a microstrip line with 50 ohm impedance and 3.3mm width and then connected with a 50 ohm matched load. The switch is controlled to be closed by controlling the bias voltage of the PIN switch diode, and when the PIN diode I and the PIN diode II are closed, the lower pass band of the filter is opened; when the first PIN diode and the second PIN diode are opened, the lower pass band of the filter is closed.

And the right arm of the U resonator of the SIR resonator II is connected with a PIN diode III, the other end of the PIN diode III is connected with a quarter-wavelength terminal open circuit, the length is 7mm, and the width is 1.26 mm. And the left arm of the U resonator of the SIR resonator III is connected with a PIN diode IV, the other end of the PIN switch diode is connected with a microstrip line with the impedance of 50 ohms and the width of 3.3mm, and then the microstrip line is connected with a 50-ohm matched load. The switch is controlled to be closed by controlling the bias voltage of the PIN switch diode, and when the PIN diode III and the PIN diode IV are closed, the upper passband of the filter is opened; when PIN diode three and PIN diode four are opened, the upper pass band of the filter is closed.

As shown in fig. 3, 4, 5, and 6, the results are the simulation results of the bandpass scattering parameters under four switching conditions of the reconfigurable filter of the present invention. From the simulation result, when the two pass bands are both started, the center frequency of the lower pass band is 2.5GHz, the 3dB bandwidth is 230MHz, the relative bandwidth is 9.2%, and the in-band insertion loss is less than 0.6 dB; the center frequency of the upper passband is 5.7GHz, the 3dB bandwidth is 440MHz, the relative bandwidth is 7.2%, and the in-band insertion loss is less than 1 dB. When the lower pass band is started and the upper pass band is closed, the center frequency of the lower pass band is 2.5GHz, the 3dB bandwidth is 240MHz, the relative bandwidth is 9.2%, and the in-band insertion loss is less than 1.5 dB. When the lower passband is closed and the upper passband is opened, the center frequency of the upper passband is 5.7GHz, the 3dB bandwidth is 410MHz, the relative bandwidth is 7.2%, and the in-band insertion loss is less than 1 dB. When both the upper and lower pass bands are closed, the filter has a minimum attenuation of-18 dB in the 1-7GHz band. It can be concluded that: before and after the frequency switching of the double-frequency-band reconfigurable filter based on the SIR loading PIN diode structure, the performance of the passband filter is basically kept unchanged, and the mutual influence of the upper passband and the lower passband is very small.

Claims

1. A double-frequency-band reconfigurable filter based on an SIR loaded PIN diode structure is characterized by comprising a dielectric substrate (1), a microstrip line circuit (2) printed on the dielectric substrate (1), and a metal copper clad (3) arranged below the dielectric substrate (1), wherein the metal copper clad (3) is grounded; the microstrip line circuit (2) comprises a first SIR resonator (21), a second SIR resonator (22), a third SIR resonator (23), a signal coupling line (24), an impedance matching line (25) and a filter output end (26), wherein the first SIR resonator (21) is a symmetrical U-shaped resonator and comprises a U-shaped resonator double arm (211) and a first U-shaped resonator beam (212); the SIR resonator II (22) and the SIR resonator III (23) are completely the same and are U-shaped resonators with asymmetric structures, the SIR resonator II (22) and the SIR resonator III (23) are located on the outer side of the beam (212) of the first U-shaped resonator, and the SIR resonator II (22) and the SIR resonator III (23) are symmetrical about the center line of the SIR resonator I (21); the signal coupling line (24) is arranged along gaps among the first U-shaped resonator beam (212), the SIR resonator II (22) and the SIR resonator III (23), two ends of the signal coupling line (24) are respectively connected with one end of the impedance matching line (25), the other end of the impedance matching line (25) is connected with the output end (26) of the filter, and PIN diodes are respectively loaded on the SIR resonator I (21), the SIR resonator II (22) and the SIR resonator III (23).

2. The dual-band reconfigurable filter based on the SIR-loaded PIN diode structure of claim 1, wherein one end of the U-shaped resonator dual arm (211) is connected to each end of a first U-shaped resonator beam (212), the first U-shaped resonator beam (212) is a high impedance line, and each end of the first U-shaped resonator beam (212) is connected to a coupling extension line (213) along its extending direction.

3. The dual band reconfigurable filter based on the SIR-loaded PIN diode structure of claim 1, wherein the coupling extension line (213) has a length of 2.6 mm.

4. The dual band reconfigurable filter based on the SIR-loaded PIN diode structure of claim 1, wherein the SIR resonator two (22) comprises a U-shaped resonator left arm (221), a U-shaped resonator right arm (222) and a second U-shaped resonator beam (223), the second U-shaped resonator beam (223) is a high impedance line, and ports of the U-shaped resonator left arm (221) and the U-shaped resonator right arm (222) are set to be open.

5. The dual-band reconfigurable filter based on the SIR loaded PIN diode structure as claimed in claim 4, wherein the U-shaped resonator right arm (222) of the SIR resonator two (22) is connected with a PIN diode three (283), and the other end of the PIN diode three (283) is connected with the terminal open line (263); and the left arm (221) of the U-shaped resonator of the SIR resonator III (23) is connected with a PIN diode IV (284), the other end of the PIN diode IV (284) is connected with a second impedance line (262), and the other end of the second impedance line (262) is connected with a second matched load (272).

6. The dual band reconfigurable filter based on the SIR-loaded PIN diode structure of claim 5, wherein the open termination line (263) is a quarter wavelength, the characteristic impedance of the second impedance line (262) is 50 ohms, and the impedance of the second matched load (272) is 50 ohms.

7. The dual-band reconfigurable filter based on the SIR loaded PIN diode structure as claimed in claim 1, wherein the other end of the U-shaped resonator arm (211) is connected to one end of a PIN diode I (281), the other ends of two PIN diodes I (281) are connected to one end of an impedance line I (261), and the other ends of two impedance lines I (261) are connected to a matching load I (271).

8. The dual band reconfigurable filter based on the SIR-loaded PIN diode structure of claim 7, wherein the characteristic impedance of impedance line one (261) is 50 ohms and the impedance of the matching load one (271) is 50 ohms.

9. The dual band reconfigurable filter based on the SIR-loaded PIN diode structure of claim 1, wherein the coupling pitch of the SIR resonator one (21) and the signal coupling line (24) is the same as the coupling pitch of the SIR resonator two (22) and the SIR resonator three (23) and the signal coupling line (24).

10. The dual band reconfigurable filter based on the SIR-loaded PIN diode structure of claim 1, wherein the signal coupling line (24) comprises a left signal coupling line (241) and a right signal coupling line (242), the left signal coupling line (241) and the right signal coupling line (242) being symmetric about a first SIR resonator (21) centerline.