CN100511828C - Wave-guide integrated on substrate-band-pass filter of coplanar wave-guide - Google Patents

Abstract

The filter is composed of periodic structured substrate integration wave-guide and coplanar wave-guide. Input end and output ends are setup at substrate integration wave-guide. Metal pasters are covered on upper and lower surfaces of medium substrate. There are at least two rows of metallized through holes on medium substrate. Thus, metal pasters on upper and lower surfaces are connected through the said metallized through holes. Periodic structure of coplanar wave-guide includes at least one compact type coplanar wave-guide unit, whose underside is a metal paster, in same plane. The said compact type coplanar wave-guide unit is positioned within the substrate integration wave-guide. Advantages are: small size, in favor of designing IC in millimeter microwave, realizable to traditional PCB or LTCC techniques, satisfying need of designing 3D IC in millimeter microwave, wide frequency selectivity, simple designing method, and good frequency selectivity.

Description

Substrate integration wave-guide-coplanar wave guide bandpass filter

Technical field

The present invention relates to a kind of design that can be applied to the microwave and millimeter wave circuit, also can be used for substrate integration wave-guide--the coplanar wave guide bandpass filter of the design of microwave and millimeter wave integrated circuit in SOP, the SOC equal altitudes integrated system.

Background technology

The microwave and millimeter wave band pass filter has a large amount of application in the communication system that develops rapidly.Along with the fast development of wide-band communication system, the filter of broad passband has urgent demand to having very.Utilize traditional structures such as metal ridge waveguide can form broadband microwave and millimeter wave band pass filter.But the filter of these forms at first is difficult to accomplish the relative bandwidth (〉=50%) of non-constant width, secondly the band pass filter volume ratio of these forms is huger, be difficult to other microwave and millimeter wave devices integrated, the band pass filter processing cost of the 3rd these forms is relatively more expensive, and the requirement of machining accuracy is than higher.In order to overcome these difficulties, need a kind of very wide bandwidth (〉=50%) that has, volume is little, and is in light weight, and processing cost is low, is easy to integrated microwave and millimeter wave band pass filter.

Summary of the invention

The invention provides and a kind ofly can satisfy broadband or radio ultra wide band system median filter needs, be easy to substrate integration wave-guide--coplanar wave guide bandpass filter that microwave and millimeter wave circuit in the communication system and microwave and millimeter wave high performance filter are integrated again, have volume little, be easy to integrated, processing cost is cheaper, frequency selectivity height, the lower advantage of loss.

The present invention adopts following technical scheme:

A kind of substrate integration wave-guide--coplanar wave guide bandpass filter, form by substrate integration wave-guide and co-planar waveguide periodic structure, on substrate integration wave-guide, be provided with input and output, substrate integration wave-guide comprises dielectric substrate, on dielectric substrate, be respectively equipped with metal patch on the lower surface, on dielectric substrate, at least also be provided with 2 row metal through holes, on, metal patch on the lower surface is connected by plated-through hole, the co-planar waveguide periodic structure comprises the compact co-planar waveguide unit, isoplanar that 1 bottom surface is a metal patch at least, and this compact co-planar waveguide unit, isoplanar is positioned within the substrate integration wave-guide.

Compared with prior art, the present invention has following advantage:

The present invention selects the band resistance of characteristic and co-planar waveguide periodic structure frequently to select characteristic to combine closely the high pass of substrate integration wave-guide frequently, has formed to have the broadband band-pass filter that fine frequency selects characteristic, and relative bandwidth is greater than 50%.In this Filter Structures, substrate integration wave-guide and co-planar waveguide periodic structure integrate closely, and device size greatly reduces.Whole filter utilizes traditional PCB or LTCC technology to realize, thereby helps this filter integrated in the microwave and millimeter wave circuit design; The form of co-planar waveguide periodic structure is extremely important for the performance of whole filter; The frequency that can improve device by the number that increases periodic unit easily selects characteristic.This filter can work in the bandwidth of non-constant width, and version is simple simultaneously, is easy to design.Specifically have following advantage:

1) whole filter is mainly formed by metal throuth hole and co-planar waveguide periodic structure, and co-planar waveguide periodic structure and substrate integration wave-guide integrate closely, and the size of this filter is smaller, helps the design of microwave and millimeter wave integrated circuit.Total can utilize traditional PCB or LTCC technology to realize, satisfies the design needs of microwave and millimeter wave stereo integrated circuit;

2) this filter has extraordinary frequency and selects characteristic, has lower insertion loss and higher Q value, and this is that co-planar waveguide has less metal loss and very little radiation loss because substrate integration wave-guide has higher Q value;

3) this filter design method is simple, by increasing the periodicity of co-planar waveguide unit, can greatly improve the performance of filter.

4) this filter has very wide bandwidth, can satisfy the requirement of a lot of broadband systems.

5) this filter can work in high frequency (greater than the 10GHz) microwave circuit, has lower loss simultaneously.

Description of drawings

Fig. 1 is a structural front view of the present invention.

Fig. 2 is a structure rearview of the present invention.

Fig. 3 is the partial enlarged drawing of structure A of the present invention-A cutaway view.

Fig. 4 is to test result figure of the present invention, and this test result has comprised the Insertion Loss of two sub-miniature A connectors.

Embodiment

A kind of substrate integration wave-guide--coplanar wave guide bandpass filter, form by substrate integration wave-guide and co-planar waveguide periodic structure, on substrate integration wave-guide, be provided with input 2 and output 3, substrate integration wave-guide comprises dielectric substrate 5, on dielectric substrate 5, be respectively equipped with metal patch 51 on the lower surface, 52, on dielectric substrate 5, at least also be provided with 2 row metal through holes 1, on, metal patch 51 on the lower surface, 52 by plated-through hole 1 connection, the co-planar waveguide periodic structure comprises the compact co-planar waveguide unit, isoplanar 4 that 1 bottom surface is a metal patch at least, and this compact co-planar waveguide unit, isoplanar 4 is positioned within the substrate integration wave-guide, and above-mentioned plated-through hole can be 2,3,5,8 or 11 row.In the present embodiment, the co-planar waveguide periodic structure comprises the compact co-planar waveguide unit, isoplanar 4 that 2 bottom surfaces are metal patch and is arranged in rows that the bottom surface of being adopted is that the concrete quantity of the compact co-planar waveguide unit, isoplanar 4 of metal patch can be 2,3,5 or more a plurality of at least.To test shows of the present invention: this filter has very wide bandwidth, good frequency selectivity, less insertion loss.Tested object is to utilize the 11 unit ultra broadband substrate integration wave-guide-co-planar waveguide periodic structure band pass filters (Wideband SIW-CPW Fi1ter) of having that the PCB technology realized.This filter closely combines substrate integration wave-guide and co-planar waveguide periodic structure, and it is of a size of 4.5X3.0cm ²

The present invention adopts following method to carry out adjusting to the size of substrate integration wave-guide and compact co-planar waveguide unit, isoplanar:

At first we regulate the diameter and the spacing of the metal throuth hole that constitutes substrate integration wave-guide according to the relation between rectangular waveguide and the substrate integration wave-guide:

${\mathrm{\λ}}_c\·f_c=C_0/\sqrt{{\mathrm{\μ}}_r{\mathrm{\ϵ}}_r}---\left(1.1\right)$

F in the following formula _cBe the cut-off frequency of rectangular waveguide in the rectangular waveguide commonly used, in design, get the lowest operating frequency in the operating frequency range of this filter, λ _cBe the cut-off wavelength of rectangular waveguide in the rectangular waveguide commonly used, C ₀For the propagation of light in the free space several times, μ _rBe the magnetic relative dielectric constant of rectangular waveguide medium, ε _rBe the electric relative dielectric constant of rectangular waveguide medium, we can be in the hope of the cut-off wavelength of rectangular waveguide by this formula.

λ _c＝2a _rec (1.2)

a _RecBe the rectangular waveguide width edge length of correspondence, we can be in the hope of required rectangular waveguide width edge length a by (1.2) formula _Rec1

${\mathrm{\λ}}_g=\frac{\mathrm{\λ}}{\sqrt{1-{\left(\frac{\mathrm{\λ}}{{\mathrm{\λ}}_c}\right)}^2}}---\left(1.3\right)$

Pairing operation wavelength when λ is operated in frequency f, λ _gGuide wavelength when being operated in frequency f in the rectangular waveguide, when getting frequency f when being the maximum operating frequency of filter, by (1.3) formula, we can be in the hope of the guide wavelength λ of required rectangular waveguide _G1, for bottom line reduces the leakage of substrate integration wave-guide sidewall, we choose spacing VSP between the metal throuth hole smaller or equal to 1/8th guide wavelength λ _G1, the diameter of metal throuth hole is greater than 1/32nd guide wavelength λ _G1It is also less than ten sixth guide wavelength λ simultaneously _G1

After the diameter and spacing of the metal throuth hole of having determined the formation substrate integration wave-guide, we try to achieve the spacing between the two row metal through holes that constitute substrate integration wave-guide according to following relational expression, that is the width W SIW of substrate integration wave-guide.

$\stackrel{\→}{a}=\frac{a_{\mathrm{rec}}}{\mathrm{WSIW}}={\mathrm{\ξ}}_1+\frac{{\mathrm{\ξ}}_2}{\frac{\mathrm{VSP}}{D}+\frac{{\mathrm{\ξ}}_1+{\mathrm{\ξ}}_2-{\mathrm{\ξ}}_3}{{\mathrm{\ξ}}_3-{\mathrm{\ξ}}_1}}---\left(1.4\right)$

A is a normalization factor in the following formula, and it has reflected the relation between substrate integration wave-guide and the rectangular waveguide, a _RecRelational expression between the rectangular waveguide, ξ ₁, ξ ₂, ξ ₃Be defined as follows respectively:

${\mathrm{\ξ}}_1=1.0198+\frac{0.3465}{\frac{\mathrm{WSIW}}{\mathrm{VSP}}-1.0684},$ ${\mathrm{\ξ}}_2=-0.1183-\frac{1.2729}{\frac{\mathrm{WSIW}}{\mathrm{VSP}}-1.2010},$ ${\mathrm{\ξ}}_3=1.0082-\frac{0.9163}{\frac{\mathrm{WSIW}}{\mathrm{VSP}}+0.2152}---\left(1.5\right)$

We use electromagnetism all-wave algorithm (Finite Difference-Time Domain divides algorithm) that the electronic band gap structure that compact co-planar waveguide unit, isoplanar constitutes is carried out Electromagnetic Simulation, thereby obtained the stop-band frequency of electronic band gap structure, we are optimized the electronic band gap structure through electromagnetism all-wave algorithm, make the stop-band frequency of electronic band gap structure and the upper limit operating frequency of this filter equate, thereby obtained the size of electronic band gap unit.

Claims (1)

1, a kind of substrate integration wave-guide-coplanar wave guide bandpass filter, it is characterized in that by substrate integration wave-guide and bottom surface being that the co-planar waveguide unit, isoplanar (4) of metal patch is formed, on substrate integration wave-guide, be provided with input (2) and output (3), described substrate integration wave-guide comprises dielectric substrate (5), on dielectric substrate (5), be respectively equipped with metal patch (51 on the lower surface, 52), on dielectric substrate (5), at least also be provided with 2 row metal through holes (1), on, metal patch (51 on the lower surface, 52) connect by plated-through hole (1), form the periodic structure of described filter by at least 2 described bottom surfaces co-planar waveguide unit, isoplanar (4) that is metal patch and the plated-through hole (1) that constitutes described substrate integration wave-guide jointly.

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