CN211428318U

CN211428318U - Band-pass or band-stop reconfigurable HMSIW filter

Info

Publication number: CN211428318U
Application number: CN201920953345.7U
Authority: CN
Inventors: 董元旦; 杨涛; 朱谊龙
Original assignee: Chengdu Pinnacle Microwave Co Ltd
Current assignee: Chengdu Pinnacle Microwave Co Ltd
Priority date: 2019-06-24
Filing date: 2019-06-24
Publication date: 2020-09-04
Anticipated expiration: 2029-06-24

Abstract

The utility model discloses a band-pass or band-stop reconfigurable Half-Mode Substrate Integrated Waveguide (HMSIW: Half Mode Substrate Integrated Waveguide) filter, which comprises two layers of medium substrates, a middle metal layer arranged between the two layers of medium substrates, and a bottom layer metal and a top layer metal respectively arranged on the surface of the medium substrates; the top metal layer comprises a microstrip structure, a medium substrate between the bottom metal layer and the middle metal layer is provided with a plurality of connecting holes, and both sides of the middle metal layer are provided with coupling grooves to form a half-mode substrate integrated waveguide resonant cavity structure. The utility model discloses a structure of half mode substrate integrated waveguide for the area of wave filter reduces half, does benefit to the miniaturization of wave filter, changes in the system integration.

Description

Band-pass or band-stop reconfigurable HMSIW filter

Technical Field

The utility model relates to a radio frequency integrated circuit filter in thing networking equipment or cell-phone particularly, relates to a band-pass or band stop reconfigurable Half Mode Substrate Integrated Waveguide (HMSIW) filter.

Background

The filter is one of the key devices at the front end of the communication system, and the ability of separating useful signals is very important in the large background of scarce spectrum resources, which directly determines the performance of the whole wireless communication system. At present, filters are widely applied to devices and equipment in the fields of radars, mobile communication, detection, aerospace and the like, and with the arrival of the 5G communication era and the wide prospect of the internet of things technology, the requirements on the filters are further increased, and higher and more severe requirements are provided for various performance indexes, such as miniaturization, high integration degree and high selectivity of the filters and reconfigurability of the filters, including center frequency reconfiguration, bandwidth reconfiguration, band-pass/band-stop reconfiguration and the like. The reconfigurable filter can dynamically tune the structure or parameters of the filter, so that the reconfigurable filter can show different filtering performances to meet the requirements of different occasions. The band-pass/band-pass reconfigurable filter is used as one type of filter, useful signals can be filtered under the condition of a pass band, strong interference signals are inhibited under the condition of a stop band, and the band-pass and the band-stop are integrated on the same filter, so that the situation that a band-pass filter and a band-stop filter are used separately in a system is avoided, and the miniaturization of the system can be realized under the limited size.

For the existing filter capable of realizing band-pass and band-stop responses, a band-pass filter and a band-stop filter can be respectively used, and switches are used for switching different channels to realize the band-pass and band-stop responses. In addition, Eric j. naglic et al published in the journal "IEEE transaction ON MICROWAVE resonance AND tech requests" entitled "adjustable band-to-band Reconfigurable Filter With independent band-to-band With resonant Response Shape" by using a three-layer metal structure, the metallized via holes form a cylindrical resonant cavity ON the bottom layer substrate layer, AND MICROWAVE signals are passed through different coupling paths from the input port to the output port by switching ON AND off the electrically controlled radio frequency switch, thereby obtaining band-pass AND band-stop responses of the Filter, respectively.

In the existing scheme, a band-pass filter and a band-stop filter are respectively adopted, and a switch is utilized to realize the switching of band-pass response channels and band-stop response channels. The biggest defect of the method is that because two filters are used, the occupied area is large, the two filters are difficult to integrate on a limited size, and the miniaturization and integration of the system are not facilitated; in addition, the band-pass response and the band-stop response are both provided with the intervention of a switch, so that the insertion loss is increased.

The band-pass/band-stop reconfigurable filter mentioned in the above article is composed of a three-layer metal structure, a cylindrical resonant cavity is formed between a middle layer metal and a bottom layer metal by utilizing metallization, and the band-pass/band-stop response can be controlled by two switches. The switch is used for switching a coupling channel of a microwave signal, and when the switch is disconnected, the signal forms a pass band through the two cylindrical resonant cavities; when the band-pass is switched, the signal forms a stop band at the output port through the two coupling paths. The reconfigurable filter adopts a cylindrical resonant cavity, and the defect is that the size of the filter is relatively large.

SUMMERY OF THE UTILITY MODEL

An object of the utility model is to provide a band-pass or band stop reconfigurable HMSIW (Half mould substrate Integrated Waveguide) wave filter adopts the structure of Half mould substrate Integrated Waveguide for the area of wave filter reduces Half, does benefit to the miniaturization of wave filter, changes in system integration more.

In order to achieve the technical purpose, the utility model discloses a technical scheme specifically as follows:

a band-pass or band-stop reconfigurable HMSIW filter, characterized by: the metal-clad laminate comprises two dielectric substrates, a middle metal layer arranged between the two dielectric substrates, and a bottom metal layer and a top metal layer which are respectively arranged on the surfaces of the dielectric substrates; the top metal layer comprises a microstrip structure, a medium substrate between the bottom metal layer and the middle metal layer is provided with a plurality of connecting holes, and both sides of the middle metal layer are provided with coupling grooves to form a half-mode substrate integrated waveguide resonant cavity structure.

Further, the equivalent microstrip routing length between the coupling grooves on the two sides of the middle metal layer is λ_g，λ_gA waveguide wavelength at the filter center frequency.

Furthermore, the microstrip structure includes a microstrip trace, a radio frequency switch loaded on the microstrip trace, and a dc bias circuit of the radio frequency switch, where the radio frequency switch and the dc bias circuit are symmetrically arranged, and the number of the radio frequency switches is even.

Furthermore, the number of the radio frequency switches is two, and the two radio frequency switches are respectively arranged at a distance lambda from the coupling groove_gAnd a microstrip loop is arranged between the two radio frequency switches at the position/4.

Furthermore, the microstrip loop is in a central symmetry structure, and 180-degree phase delay is formed between the two radio frequency switches to form lambda_gAnd/2 equivalent microstrip trace length.

Furthermore, two sides of the radio frequency switch are respectively provided with a blocking capacitor.

Further, the microstrip structure further comprises a direct current feeding part for controlling the on and off of the two switches.

Further, when the radio frequency switches are all disconnected, the microstrip line is equivalently short-circuited at the coupling slot, and signals are output from the microstrip line through the half-mode substrate integrated waveguide resonant cavity to form the second-order band-pass filter.

Further, when the radio frequency switches are all conducted, phase difference of one part of signals from the input end coupling groove to the output end coupling groove is 360 degrees, the other part of signals are output through the two half-mode substrate integrated waveguide resonant cavities, the phase difference of the signals at the position, where the input end coupling groove is located, of the output end coupling groove is 180 degrees, the signals are mutually offset to form a stop band, and therefore the band-stop filter is formed.

The beneficial effects of the utility model reside in that: the utility model is different from the prior art, the utility model provides a band-pass/band stop reconfigurable filter, break-make through two automatically controlled switches forms the coupling passageway of two kinds of differences on the wave filter physical structure to obtain the band stop response and the band-pass response of wave filter respectively. The tunable band-pass/band-stop filter has the characteristics of flexibility and adjustability, can realize the switchability of band-pass/band-stop on the same filter, and is beneficial to the miniaturization design of a system.

The two radio frequency switches of the filter are loaded at a position which is far from a coupling groove lambda g/4, and the bandpass response of the filter is realized by utilizing the open circuit at the tail end of the microstrip line and the short circuit at the position which is far from the tail end lambda g/4 when the switches are in an off state. The band-pass response and the band-stop response of the filter are controlled by using the switches respectively, and the insertion loss of the filter in the band-pass response is reduced.

The filter adopts two rectangular half-mode substrate integrated waveguide resonant cavities, and compared with the traditional full-mode SIW filter, the area of the filter is reduced by half, so that the occupied area of the filter is smaller.

Drawings

Fig. 1 is a schematic diagram of an expanded structure of a band-pass or band-stop reconfigurable HMSIW filter provided by the present invention;

fig. 2 is a schematic side view of a band-pass or band-stop reconfigurable HMSIW filter provided by the present invention;

fig. 3 is a band-pass parameter diagram when the rf switch of the HMSIW filter with reconfigurable band-pass or band-stop provided by the present invention is turned off;

fig. 4 is a band-stop parameter diagram when the rf switch of the HMSIW filter with reconfigurable band-pass or band-stop provided by the present invention is turned on;

reference numerals:

1 is a dielectric substrate, 2 is a top layer metal, 3 is a middle layer metal, 4 is a coupling groove, 5 is a bottom layer metal, 6 is a connecting hole, 7 is a radio frequency switch, 8 is a blocking capacitor C1, 9 is an alternating current isolating inductor L1, 10 is an isolating inductor C2, and 11 is a current limiting resistor R1.

Detailed Description

The present invention will be described in further detail below with reference to specific embodiments and with reference to the accompanying drawings.

As shown in fig. 1-2, a band-pass or band-stop reconfigurable HMSIW filter includes two dielectric substrates 1, an intermediate metal layer disposed between the two dielectric substrates 1, and a bottom metal 5 and a top metal 2 respectively disposed on the surfaces of the dielectric substrates 1.

The top layer metal 2 comprises a microstrip structure, the microstrip structure comprises a microstrip line, a radio frequency switch 7 loaded on the microstrip line and a direct current bias circuit of the radio frequency switch 7, the radio frequency switch 7 and the direct current bias circuit are symmetrically arranged, and the number of the radio frequency switches 7 is even. Specifically, the radio frequency switches 7 are two and are respectively marked as D1 and D2, and D1 and D2 are arranged at a distance of 4 lambda from the coupling groove_gAt position/4.

A micro-strip loop is arranged between the two radio frequency switches 7, the micro-strip loop is in a central symmetrical structure, and 180-degree phase delay is formed between the two radio frequency switches 7 to form lambda_gAnd/2 is equivalent to the microstrip routing length, and two sides of the two radio frequency switches 7 are respectively provided with a blocking capacitor C1 (8).

The dc bias circuit includes an isolated inductor L1(9) of 20nH, a current limiting resistor R1(11) of 100 ohms, and an isolated inductor C2(10) of 20pF, all of which adopt the 0402 standard package structure. The microstrip structure also comprises a direct current feed part for controlling the on-off of the two switches. The dielectric substrate 1 between the bottom metal 5 and the middle metal layer is provided with a plurality of connecting holes 6, and both sides of the middle metal layer are provided with coupling grooves 4, so that a half-mode substrate integrated waveguide resonant cavity structure is formed. The equivalent microstrip routing length between the coupling grooves 4 at the two sides of the middle metal layer is lambda_g，λ_gA waveguide wavelength at the filter center frequency.

When the radio frequency switches 7 are all disconnected, the microstrip line is equivalently short-circuited at the coupling slot 4, and signals are output from the microstrip line through the half-mode substrate integrated waveguide resonant cavity to form a second-order band-pass filter.

When the radio frequency switches 7 are all conducted, a phase difference of a part of signals from the input end coupling slot 4 to the output end coupling slot 4 is 360 degrees, the other part of signals are output through the two half-mode substrate integrated waveguide resonant cavities, the phase difference of the signals at the position, where the input end coupling slot 4 is located in the output end coupling slot 4, is 180 degrees, the signals are mutually offset to form a stop band, and therefore the band-stop filter is formed.

When specifically using, the utility model discloses a false four-layer plate structure of PCB processing technology preparation, two-layer 0.508mm thick medium base plate 1, medium layer about the medium plate is 0.018 mm's metallic copper layer to and constitute such as metallized via hole. The dielectric substrate 1 used herein was a Tastic tly DK2.2 substrate having a relative dielectric constant of 2.2 and a loss tangent of 0.0009. The middle layer metal 3 is provided with two slender grooves to form two half-mode substrate integrated waveguide resonant cavity structures; the resonator is tuned to resonate at 5GHz, and thus the filter center frequency is also at 5 GHz. The top layer metal 2 is a 50 omega microstrip line structure,two radio frequency switches 7D1 and D2 (the radio frequency switch 7 uses MA4SW110 model) are loaded on the microstrip line respectively, and the loading positions of the radio frequency switches 7D1 and D2 are respectively away from the notch lambda_g(ii)/4; when the switch is turned on, the phase delay from the D1 input to the D2 output is 180 DEG, which is equivalent to lambda, after considering a certain phase delay brought by the switch itself_g2, the length of the microstrip line between the two slots is therefore equivalent to λ_g。

When supplied with-1.5V dc, the rf switches 7D1 and D2 are open, and the microstrip lines are open at this point, due to the switch position at about λ from the two coupling slots 4_gAnd 4, the microstrip line is equivalent to a short circuit at the coupling slot 4, so that signals can be coupled through the slot to perform half-mode substrate integrated waveguide resonant cavities, the filter is of a symmetrical structure, and the signals are output from the microstrip line through the two resonant cavities to form a second-order band-pass filter. The resonance frequency of the resonator is set at 5GHz because a band-pass filter having a center frequency of 5GHz is constructed. As shown in fig. 3, is the bandpass response S parameter of the filter. It can be seen that two transmission poles are generated in the S parameter and are formed by two half-mode substrate integrated waveguide resonant cavities; and a transmission zero at 6.5GHz due to the open, open lambda of the switch_gThe/4 microstrip line resonance is generated.

When the direct current supplies +1.5V, the radio frequency switches 7D1 and D2 are conducted, and the microstrip line is conducted from the input port to the output port. At this time, the length of the microstrip line between the two coupling grooves 4 is equivalent to lambda_gThe phase difference of the signals from the input end coupling groove 4 to the output end coupling groove 4 is 360 degrees; in addition, another part of signals are coupled into the half-mode substrate integrated waveguide resonant cavity from the coupling slot 4, the signals are output through the two half-mode substrate integrated waveguide resonant cavities, and the phase difference of the signals on the path is 180 degrees when the input end coupling slot 4 is positioned at the output end coupling slot 4. Therefore, at the output end coupling slot 4, the electromagnetic signals on the two paths have approximately the same amplitude, but are 180 ° out of phase, and the signals cancel each other out to form a stop band. As shown in fig. 4, which is the stop band response of the filter, it can be seen that there is some shift in the center frequency and the stop band rejection is greater than 20 dB.

The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention, and various modifications and changes may be made by those skilled in the art. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. Band-pass or band-stop reconfigurable HMSIW filter, characterized in that: the metal-clad laminate comprises two dielectric substrates, a middle metal layer arranged between the two dielectric substrates, and a bottom metal layer and a top metal layer which are respectively arranged on the surfaces of the dielectric substrates; the top metal layer comprises a microstrip structure, a medium substrate between the bottom metal layer and the middle metal layer is provided with a plurality of connecting holes, and both sides of the middle metal layer are provided with coupling grooves to form a half-mode substrate integrated waveguide resonant cavity structure.

2. The band-pass or band-stop reconfigurable HMSIW filter of claim 1, wherein: the equivalent microstrip routing length between the coupling grooves on the two sides of the middle metal layer is lambda_g，λ_gA waveguide wavelength at the filter center frequency.

3. The band-pass or band-stop reconfigurable HMSIW filter of claim 1, wherein: the microstrip structure comprises a microstrip line, a radio frequency switch loaded on the microstrip line and a direct current bias circuit of the radio frequency switch, wherein the radio frequency switch and the direct current bias circuit are symmetrically arranged, and the number of the radio frequency switches is even.

4. A band-pass or band-stop reconfigurable HMSIW filter according to claim 3, characterized in that: the two radio frequency switches are respectively arranged at a distance lambda from the coupling groove_gAnd a microstrip loop is arranged between the two radio frequency switches at the position/4.

5. The band-pass or band-stop reconfigurable HMSIW filter of claim 4, wherein: the microstrip loop has a centrosymmetric structure180 DEG phase delay is formed between the two radio frequency switches to form lambda_gAnd/2 equivalent microstrip trace length.

6. A band-pass or band-stop reconfigurable HMSIW filter according to any of claims 3 to 5, characterized in that: and two sides of the radio frequency switch are respectively provided with a blocking capacitor.

7. A band-pass or band-stop reconfigurable HMSIW filter according to claim 3, characterized in that: the microstrip structure also comprises a direct current feed part for controlling the on-off of the two switches.

8. The band-pass or band-stop reconfigurable HMSIW filter of claim 6, wherein: when the radio frequency switches are all disconnected, the microstrip line is equivalently short-circuited at the coupling slot, and signals are output from the microstrip line through the half-mode substrate integrated waveguide resonant cavity to form the second-order band-pass filter.

9. The band-pass or band-stop reconfigurable HMSIW filter of claim 6, wherein: when the radio frequency switches are conducted, the phase difference of one part of signals from the input end coupling groove to the output end coupling groove is 360 degrees, the other part of signals are output through the two half-mode substrate integrated waveguide resonant cavities, the phase difference of the signals at the position, where the input end coupling groove is located, of the output end coupling groove is 180 degrees, the signals are mutually offset to form a stop band, and therefore the band-stop filter is formed.