CN107565195A

CN107565195A - Microwave filter

Info

Publication number: CN107565195A
Application number: CN201710716542.2A
Authority: CN
Inventors: 韩默; 冯东; 保琛; 靳艳
Original assignee: Chengdu Yi Xin Technology Co Ltd
Current assignee: Chengdu Yi Xin Technology Co Ltd
Priority date: 2017-08-21
Filing date: 2017-08-21
Publication date: 2018-01-09

Abstract

The invention discloses a kind of microwave filter, is related to microwave electron systems technology field, including the metallic plate to lower and upper setting, first medium substrate, second medium substrate, half module pectination substrate integration wave-guide layer and bimodulus resonant element layer；Second medium substrate is provided with through hole, and the upper surface of second medium substrate sets coplanar input waveguide feeder line and output waveguide feeder line, and the lower surface of second medium substrate sets microstrip line, and waveguide feeder is connected by through hole with microstrip line；Microstrip line is connected by impedance transformer with the metal covering of the upper surface of half module pectination substrate integration wave-guide layer；The both sides of input waveguide feeder line and output waveguide feeder line set a coplanar waveguide metal ground plane respectively.Compared with prior art, the present invention solves the problems, such as that radiation loss is high, discontinuous adjustable and tuning bandwidth is narrow.

Description

Microwave filter

Technical field

It is especially a kind of to be used to enter line frequency choosing during microwave transmission the present invention relates to microwave electron systems technology field The microwave filter selected.

Background technology

Wave filter is as a kind of device with frequency selectivity in microwave electron system, to microwave circuit, system Function produces important influence.

Existing microwave filter mainly mainly includes ripple using transmission line type and two kinds of structures of lumped element type, transmission line type Conductivity type, stripline and micro strip line type etc., the deficiency of waveguide type are that size is larger, are unfavorable for system compact, integrated；Band The deficiency of shape line style is there is larger radiation loss；Deficiency existing for micro strip line type is that physical size is too small and is not easy to add Work.Existing microwave filter realizes that the tunable technology of tunable optic filter is mainly：PIN diode tuning, Ferrite Material are adjusted Humorous, mems device tuning is realized.The deficiency of PIN diode tuning is that discontinuous tuning, poor linearity can only be realized And biasing circuit is more complicated；The deficiency of Ferrite Material tuning is that the BREATHABLE BANDWIDTH that can realize is narrower；Mems device Deficiency existing for tuning is that operating voltage is high, cost is larger.With the high speed development and frequency spectrum resource of microwave electron technology A kind of anxiety, microwave filter with advantages such as continuously adjustabe, miniaturization, high-performance, low costs of design, becomes development Inexorable trend.

The content of the invention

The technical problems to be solved by the invention are to provide a kind of microwave filter, and it can solve body of the prior art The problem of product is big, radiation loss is high, discontinuous adjustable and tuning bandwidth is narrow.

In order to solve the above problems, the technical solution adopted in the present invention is：This microwave filter, including to it is lower and on Metallic plate, first medium substrate, second medium substrate, half module pectination substrate integration wave-guide layer and the bimodulus resonant element of setting Layer；The second medium substrate is provided with through hole, and the upper surface of the second medium substrate sets coplanar input waveguide feeder line With output waveguide feeder line, the lower surface of the second medium substrate sets microstrip line, the input waveguide feeder line and output waveguide Feeder line is connected by the through hole with the microstrip line；The microstrip line passes through impedance transformer and the half module pectination substrate collection Metal covering into the upper surface of ducting layer connects；The both sides of the input waveguide feeder line and output waveguide feeder line are set altogether respectively Face waveguide metal ground plane；The bimodulus resonant element layer is located at the surrounding of the half module pectination substrate integration wave-guide layer；It is described Second medium substrate is provided with the hand-hole for being used for injecting liquid crystal material, and the first medium substrate is the ring of middle hollow out groove Shape；Voltage is loaded into the both ends of the input waveguide feeder line and the output waveguide feeder line respectively.

In above-mentioned technical proposal, more specifically technical scheme can also be：The metallic plate and the first medium substrate Pass through conductive glue bond；The first medium substrate passes through conductive glue bond with the second medium substrate.

Further：The bimodulus resonant element is the square structure of opening.

Further：The half module pectination substrate integration wave-guide layer is the pectination microstrip line construction equidistantly arranged, described The separation of two metal layers up and down of half module pectination substrate integration wave-guide layer.

By adopting the above-described technical solution, the present invention has the advantages that compared with prior art：

1st, half module pectination substrate integrated wave guide structure, while the tunable property based on liquid crystal material, pass through load-modulate Voltage signal, change dielectric constant by changing the voltage of liquid crystal material so that obtain the frequency response of continuously adjustabe, have Continuous adjustability；There is some of conventional waveguide and microstrip transmission line advantages, Q simultaneously using half module pectination substrate integration wave-guide layer Value compared with high, loss compared with it is small, power capacity is big, broader bandwidth, while belongs to planar structure again, easy to process, be easily integrated, volume It is small.

2nd, the two metal layers up and down of half module pectination substrate integration wave-guide layer are separation, to the liquid crystal material based on the structure The Design of microwave filters of material, only with the mode of conducting resinl bonding packaging liquid crystal material can be realized in metallic plate and first medium Fixed and liquid crystal material encapsulation between substrate, and realize that upper and lower plates are also not present in good matching between second medium substrate The problem of short-circuit.

3rd, by first medium substrate and second medium substrate, the mode of through-hole interconnection between second medium substrate and metallic plate The half module pectination substrate integration wave-guide lower metal layer of liquid crystal material contact portion is transitioned into upper metal layers has fixed hinder Anti- coplanar waveguide structure, and reach between through hole and lower metal layer the mesh of impedance matching using the method for transition of mechanical impedance , so as to solve impedance mismatch problem.

4th, the structure of the bimodulus resonant element layer of square aperture, input waveguide feeder line and output waveguide are fed using contact Feeder line so maintains the low frequency channel of whole microwave filter, to load low frequency by the way of direct contact type feed Modulation voltage, so as to solve the problems, such as that traditional broadside lotus root conjunction wave filter can not load-modulate voltage due to discontinuity.

Brief description of the drawings

Fig. 1 is assembly structure diagram.

Fig. 2 is overall structure diagram.

Fig. 3 is Fig. 2 top view.

Fig. 4 is Fig. 2 front view.

Fig. 5 is Fig. 2 side view.

Embodiment

Below in conjunction with accompanying drawing embodiment, the invention will be further described：

Microwave filter as depicted, including metallic plate 1, first medium substrate 2, half module pectination to lower and upper setting Substrate integration wave-guide layer 4, second medium substrate 3 and bimodulus resonant element layer 5；The metallic plate 1 is made by mechanical processing toolses.

The lower surface of second medium substrate 3 sets coplanar input waveguide feeder line 8 and output waveguide feeder line 9, input waveguide Feeder line 8 respectively connects the following table positioned at second medium substrate 3 with the end of output waveguide feeder line 9 by metalized signal through hole The microstrip line 10 in face, the microstrip line 10 are connected by the upper metal covering of impedance transformer 13 and half module pectination substrate integration wave-guide layer 4 Connect, what the two metal layers up and down of half module pectination substrate integration wave-guide layer 4 were completely separate；Input waveguide feeder line 8 and output wave Lead the both sides of feeder line 9 and one coplanar waveguide metal ground plane 12 is respectively set, opened on the upper metal covering of half module pectination substrate integration wave-guide layer 4 Provided with unclosed square bimodulus resonant element 5, second medium substrate 3 is provided with liquid crystal material hand-hole 7；First layer medium Substrate 2 is ring-type, and centre is hollow out groove, by the liquid crystal material hand-hole 7 that second medium substrate 3 is provided with toward first medium The hollow out groove part injection liquid crystal material of substrate 2, liquid crystal material flow to metallic plate 1, then encapsulated liquid crystals hand-hole again, gold After belonging to plate 1 and the bonding of first medium substrate 2, liquid crystal material part forms liquid crystal layer 11.

During installation, bonded first by first medium substrate 2 by conducting resinl 6 with metallic plate 1 together with, then by second medium Substrate 3 and first medium substrate 2 by conductive glue bond together with, then pass through the liquid crystal hand-hole reserved on second medium substrate 3 Inside the hollow out groove on liquid crystal material injection second medium substrate 2.

When modulation voltage loading input waveguide feeder line 8 and output waveguide feeder line 9, radiofrequency signal is produced, is situated between via second The upper strata input port of matter substrate 3 is input to institute's half module pectination substrate integration wave-guide layer 4, then is integrated by the half module pectination substrate Ducting layer 4 is transported to first medium substrate 2, reaches liquid crystal layer 11；First medium substrate 2 is reached by liquid crystal layer during output, so The output port of second medium substrate 3 is reached afterwards, then signal is fed into half module pectination substrate integration wave-guide layer 4.When modulation electricity It is parallel to each other between the major axis of the liquid crystal molecule of liquid crystal layer when pressing the peak amplitude of signal to be 0, and parallel to first medium substrate 2, dielectric constant now is smaller.When the peak amplitude increase of modulated voltage signal, the sensing of the liquid crystal molecule of liquid crystal layer 11 Gradually it can be deflected to direction of an electric field, when modulation voltage is sufficiently high and reaches the saturation voltage of the liquid crystal molecule, the liquid The polarization of crystal layer reaches saturation, and the dielectric constant of the liquid crystal layer increases and reaches maximum therewith in the process.

Because the dielectric constant of the liquid crystal layer 11 can change with the change of modulation voltage, cause bimodulus resonant element The electrical length of layer 5 changes with the change of liquid crystal dielectric constant, so as to which bimodulus resonant frequency changes therewith, thus it is final real When now connecting work, radiofrequency signal and modulated voltage signal are added by 50 ohm of coplanar waveguide feeder lines of input and output, then Change the dielectric constant of liquid crystal layer by changing the amplitude of modulation voltage, finally give the frequency response of continuously adjustabe.

Claims

A kind of 1. microwave filter, it is characterised in that：Including the metallic plate to lower and upper setting, first medium substrate, half module comb Shape substrate integration wave-guide layer, second medium substrate and bimodulus resonant element layer；The lower surface of the second medium substrate is set altogether The input waveguide feeder line and output waveguide feeder line in face, the lower surface of the second medium substrate set microstrip line, the incoming wave Lead feeder line and the output waveguide feeder line is connected with the microstrip line；The microstrip line is combed by impedance transformer and the half module The metal covering connection of the upper surface of shape substrate integration wave-guide layer；The both sides of the input waveguide feeder line and the output waveguide feeder line One coplanar waveguide metal ground plane is set respectively；The bimodulus resonant element layer is located at the half module pectination substrate integration wave-guide layer Surrounding；The second medium substrate is provided with the hand-hole for being used for injecting liquid crystal material, and the first medium substrate is centre The ring-type of hollow out groove；Voltage is loaded into the both ends of the input waveguide feeder line and the output waveguide feeder line respectively.
2. microwave filter according to claim 1, it is characterised in that：The metallic plate leads to the first medium substrate Cross conductive glue bond；The first medium substrate passes through conductive glue bond with the second medium substrate.
3. microwave filter according to claim 2, it is characterised in that：The bimodulus resonant element is the square knot of opening Structure.
4. microwave filter according to claim 3, it is characterised in that：The half module pectination substrate integration wave-guide layer for etc. The pectination microstrip line construction of spacing arrangement, the separation of two metal layers up and down of the half module pectination substrate integration wave-guide layer.