CN100334775C - Wave-guide integrated on substrate-electronic band gap band pass filter - Google Patents

Abstract

The invention discloses a substrate-integrated waveguide-electronic bandgap bandpass filter, which comprises: a dielectric substrate coated with metal patches serving as the top surface and the ground respectively on both sides; The waveguide has an electronic bandgap structure on the ground, and an input terminal and an output terminal are provided on the top surface and are respectively connected to the integrated waveguide of the same substrate. The electronic bandgap structure is composed of coplanar compact electronic bandgap units arranged in an array. The present invention has the following advantages: the filter tightly integrates the electronic bandgap structure (PBG) and the substrate integrated waveguide (SIW), the device size is relatively small, and it is easy to integrate with other circuits in the design of microwave and millimeter wave circuits to meet Requirements for low-cost large-scale processing; high-performance frequency selectivity can be achieved in a wide frequency range, the design method is relatively simple, and the number of structural units with the same electronic bandgap can be increased between the input end and the output end. Greatly increases the frequency-selective properties of the filter.

Description

Substrate Integrated Waveguide-Electronic Bandgap Bandpass Filter

technical field

The invention relates to a substrate integrated waveguide that can be applied to the design of microwave and millimeter wave circuits, and can also be used in the design of microwave and millimeter wave integrated circuits in highly integrated systems such as system package (SOP) and system on chip (SOC) -- electronic bandgap bandpass filter.

Background technique

Microwave and millimeter wave bandpass filters have a large number of applications in rapidly developing communication systems. With the rapid development of broadband communication systems, there is an urgent need for filters with very wide passbands. Broadband microwave and millimeter wave bandpass filters can be formed using traditional structures such as metal ridge waveguides. However, it is difficult for these forms of filters to achieve a very wide relative bandwidth (≥50%). Secondly, these forms of bandpass filters are relatively bulky and difficult to integrate with other microwave and millimeter wave devices. Thirdly, these forms of bandpass filters The cost of filter processing is relatively expensive, and the requirements for processing accuracy are relatively high. In order to overcome these difficulties, there is a need for a microwave and millimeter wave bandpass filter with a wide bandwidth (≥50%), small size, light weight, low processing cost, and easy integration.

Contents of the invention

The invention provides a substrate-integrated waveguide-electronic bandgap that can meet the needs of filters in broadband or ultra-wideband systems and is easy to integrate microwave and millimeter wave circuits in communication systems with microwave and millimeter wave high-performance filters. Pass filter, which has the advantages of small size, easy integration, relatively low processing cost, and good frequency selectivity, and is especially suitable for mass production and the design of microwave and millimeter wave integrated circuits.

The present invention adopts following technical scheme:

A substrate-integrated waveguide-electronic bandgap band-pass filter, comprising: a dielectric substrate covered with metal patches as the top surface and the ground respectively on both sides, a substrate-integrated waveguide is arranged on the dielectric substrate, the substrate The chip integrated waveguide consists of at least 2 rows of metallized through holes, the metal patches are connected by metallized through holes, an electronic bandgap structure is set on the ground of the dielectric substrate, and an input terminal and The output ends are respectively connected to the same substrate integrated waveguide, the electronic bandgap structure is composed of coplanar compact electronic bandgap units arranged in an array, and at least one row of coplanar compact electronic bandgap units is located in the inner area of the substrate integrated waveguide On the ground of the substrate, the metallized through-holes used to form the substrate integrated waveguide are respectively located in each electronic bandgap unit of the 2 rows of coplanar compact electronic bandgap units, and the 2 rows of coplanar compact electronic bandgap units are respectively located in the base Both sides of the coplanar compact electronic bandgap unit in the inner region of the sheet-integrated waveguide.

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

The invention utilizes two or more rows of metallized through holes on a dielectric substrate to form a substrate integrated waveguide. The invention utilizes the high-pass frequency selection characteristics of the substrate-integrated waveguide and the band-stop characteristic of the electronic bandgap structure, and combines the electronic bandgap structure closely with the substrate-integrated waveguide to form a high-performance filter. volume is greatly reduced. In the structure of this filter, all structures can be realized by using traditional PCB or LTCC technology, and the whole structure is mainly composed of a series of metal through-hole arrays on the dielectric substrate, thereby reducing production costs and benefiting The integration of this filter in microwave and millimeter wave circuit design; we designed a better broadband input and output coupling structure and tightly integrated the electronic bandgap structure with the substrate integrated waveguide; the realization of this filter It is mainly realized by utilizing the high-pass frequency selection characteristics of the substrate integrated waveguide and the band-rejection characteristics of the electronic bandgap structure. By adjusting the size of the substrate-integrated waveguide and the electronic bandgap structure, a substrate-integrated waveguide-electronic bandgap bandpass filter with very wide frequency band and excellent selectivity can be formed; the design method of this filter is simple and can be passed Increasing the number of structural units with the same electronic bandgap greatly increases the frequency selection characteristics of the filter. The present invention specifically has the following advantages:

1) This filter tightly integrates the electronic bandgap structure (PBG) and the substrate integrated waveguide (SIW), the device size is relatively small, and it is easy to integrate with other circuits in the design of microwave and millimeter wave circuits. This kind of filter can be realized on the dielectric substrate by using commonly used PCB or LTCC technology. The main structure of the filter is an array of metal through holes, which is compact and meets the requirements of low-cost and large-scale processing;

2) It can achieve high-performance frequency selectivity in a wide frequency band, and the design method is relatively simple. By increasing the number of the same electronic bandgap structural units between the input end and the output end, the filter can be greatly increased. Frequency selection feature.

Description of drawings

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

Fig. 2 is a rear view of the structure of the present invention.

Fig. 3 is a side view of the structure of the present invention.

Fig. 4 is a test result diagram of the embodiment of the present invention, the test result includes the insertion loss of two SMA connectors.

Fig. 5 is a structural rear view of Embodiment 1 of the present invention.

Fig. 6 is a rear view of the structure of Embodiment 2 of the present invention.

Fig. 7 is a rear view of the structure of Embodiment 3 of the present invention.

Detailed ways

A substrate-integrated waveguide-electronic bandgap bandpass filter, comprising: a dielectric substrate 3 covered with metal patches 21 and 22 as the top surface and the ground respectively on both sides, and the dielectric substrate 3 is provided with a substrate Chip integrated waveguide, the substrate integrated waveguide is composed of at least 2 rows of metallized through holes 1, the metal patches 21 and 22 are connected by metallized through holes 1, and an electronic bandgap structure is arranged on the ground of the dielectric substrate 3. The top surface of the dielectric substrate 3 is provided with an input terminal 2 and an output terminal 5 and is respectively connected to the integrated waveguide of the same substrate. The electronic bandgap structure is composed of coplanar compact electronic bandgap units 4 arranged in an array, and at least 1 The coplanar compact electronic bandgap unit is located on the ground of the inner area of the substrate integrated waveguide, and the metallized through holes used to form the substrate integrated waveguide are respectively located in each electronic bandgap unit of the 2 coplanar compact electronic bandgap units Inside, the two rows of coplanar compact electronic bandgap units are respectively located on both sides of the coplanar compact electronic bandgap units in the inner region of the substrate integrated waveguide (as shown in Figure 2, Figure 5 to Figure 7).

The aforementioned metallized through holes may be in 2, 3, 5, 8 or 11 rows. In this embodiment, there may be 1, 3, 4, 6, 9 or 12 rows of coplanar compact electronic bandgap units located on the ground in the inner region of the substrate integrated waveguide.

The test of the present invention shows that the filter has very wide bandwidth and good frequency selectivity. The test object is an 11-unit ultra-wideband substrate integrated waveguide-electronic bandgap bandpass filter (Wideband SIW-PBG Filter) realized by PCB technology. The dimensions of the filter are 5.5 x 4.2 cm ² .

The present invention adopts the following method to adjust the size of the substrate integrated waveguide and the coplanar compact electronic bandgap unit:

First, we adjust the diameter and spacing of the metal through-holes that constitute the substrate-integrated waveguide according to the relationship between the rectangular waveguide and the substrate-integrated waveguide:

${\mathrm{<span\; class="notranslate">\; \&lambda;</span>}}_{\mathrm{<span\; class="notranslate">\; c</span>}}<span\; class="notranslate">\; \&Center\; Dot;</span>{\mathrm{<span\; class="notranslate">\; f</span>}}_{\mathrm{<span\; class="notranslate">\; c</span>}}<span\; class="notranslate">\; =</span>{\mathrm{<span\; class="notranslate">\; C</span>}}_{\mathrm{<span\; class="notranslate">\; 0</span>}}<span\; class="notranslate">\; /</span>\sqrt{{\mathrm{<span\; class="notranslate">\; \&mu;</span>}}_{\mathrm{<span\; class="notranslate">\; r</span>}}{\mathrm{<span\; class="notranslate">\; \&epsiv;</span>}}_{\mathrm{<span\; class="notranslate">\; r</span>}}}<span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 1.1</span>}<span\; class="notranslate">\; )</span>$

In the above formula, f _c is the cut-off frequency of the rectangular waveguide in the commonly used rectangular waveguide, and the lowest operating frequency within the operating frequency range of the filter is taken in the design, λ _c is the cut-off wavelength of the rectangular waveguide in the commonly used rectangular waveguide, and C ₀ is the free The number of degrees of light propagation in space, μ _r is the magnetic relative permittivity of the medium in the rectangular waveguide, and ε _r is the electrical relative permittivity of the medium in the rectangular waveguide. From this formula, we can obtain the cut-off wavelength of the rectangular waveguide.

λ _c =2a _rec (1.2)

a _rec is the corresponding length of the broadside of the rectangular waveguide, and we can obtain the required length of the broadside of the rectangular waveguide a _rec1 from formula (1.2).

${\mathrm{<span\; class="notranslate">\; \&lambda;</span>}}_{\mathrm{<span\; class="notranslate">\; g</span>}}<span\; class="notranslate">\; =</span>\frac{\mathrm{<span\; class="notranslate">\; \&lambda;</span>}}{\sqrt{\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; -</span>{<span\; class="notranslate">\; (</span>\frac{\mathrm{<span\; class="notranslate">\; \&lambda;</span>}}{{\mathrm{<span\; class="notranslate">\; \&lambda;</span>}}_{\mathrm{<span\; class="notranslate">\; c</span>}}}<span\; class="notranslate">\; )</span>}^{\mathrm{<span\; class="notranslate">\; 2</span>}}}}<span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 1.3</span>}<span\; class="notranslate">\; )</span>$

λ works at the frequency f corresponding to the working wavelength, λ _g is the waveguide wavelength in the rectangular waveguide working at the frequency f, when the frequency f is taken as the highest working frequency of the filter, from (1.3) formula, we can obtain The waveguide wavelength λ _g1 of the required rectangular waveguide, in order to minimize the leakage of the substrate-integrated waveguide sidewall, we select the spacing VSP between the metal vias to be less than or equal to one-eighth of the waveguide wavelength λ _g1 , the metal vias The diameter is greater than one-thirtieth of the waveguide wavelength λ _g1 while it is also smaller than one-sixteenth of the waveguide wavelength λ _g1 .

After determining the diameter and spacing of the metal through-holes that constitute the substrate-integrated waveguide, we obtain the spacing between the two rows of metal-through-holes that constitute the substrate-integrated waveguide, that is, the width of the substrate-integrated waveguide WSIW.

$\stackrel{<span\; class="notranslate">\; \&OverBar;</span>}{\mathrm{<span\; class="notranslate">\; a</span>}}<span\; class="notranslate">\; =</span>\frac{{\mathrm{<span\; class="notranslate">\; a</span>}}_{\mathrm{<span\; class="notranslate">\; rec</span>}}}{\mathrm{<span\; class="notranslate">\; WSIW</span>}}<span\; class="notranslate">\; =</span>{\mathrm{<span\; class="notranslate">\; \&xi;</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; +</span>\frac{{\mathrm{<span\; class="notranslate">\; \&xi;</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}}{\frac{\mathrm{<span\; class="notranslate">\; VSP</span>}}{\mathrm{<span\; class="notranslate">\; D.</span>}}<span\; class="notranslate">\; +</span>\frac{{\mathrm{<span\; class="notranslate">\; \&xi;</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; \&xi;</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; \&xi;</span>}}_{\mathrm{<span\; class="notranslate">\; 3</span>}}}{{\mathrm{<span\; class="notranslate">\; \&xi;</span>}}_{\mathrm{<span\; class="notranslate">\; 3</span>}}<span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; \&xi;</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}}}<span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 1.4</span>}<span\; class="notranslate">\; )</span>$

是归一化因子，它反映了基片集成波导和矩形波导之间的关系，α_rec矩形波导之间的关系式，ξ₁，ξ₂，ξ₃分别定义如下：In the above formula

is a normalization factor, which reflects the relationship between the substrate-integrated waveguide and the rectangular waveguide, the relationship between the α _rec rectangular waveguide, ξ ₁ , ξ ₂ , ξ ₃ are defined as follows:

${\mathrm{<span\; class="notranslate">\; \&xi;</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; =</span>\mathrm{<span\; class="notranslate">\; 1.0198</span>}<span\; class="notranslate">\; +</span>\frac{\mathrm{<span\; class="notranslate">\; 0.3465</span>}}{\frac{\mathrm{<span\; class="notranslate">\; WSIW</span>}}{\mathrm{<span\; class="notranslate">\; VSP</span>}}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; 1.0684</span>}}<span\; class="notranslate">\; ,</span>$ ${\mathrm{<span\; class="notranslate">\; \&xi;</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; =</span><span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; 0.1183</span>}<span\; class="notranslate">\; -</span>\frac{\mathrm{<span\; class="notranslate">\; 1.2729</span>}}{\frac{\mathrm{<span\; class="notranslate">\; WSIW</span>}}{\mathrm{<span\; class="notranslate">\; VSP</span>}}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; 1.2010</span>}}<span\; class="notranslate">\; ,</span>$ ${\mathrm{<span\; class="notranslate">\; \&xi;</span>}}_{\mathrm{<span\; class="notranslate">\; 3</span>}}<span\; class="notranslate">\; =</span>\mathrm{<span\; class="notranslate">\; 1.0082</span>}<span\; class="notranslate">\; -</span>\frac{\mathrm{<span\; class="notranslate">\; 0.9163</span>}}{\frac{\mathrm{<span\; class="notranslate">\; WSIW</span>}}{\mathrm{<span\; class="notranslate">\; VSP</span>}}<span\; class="notranslate">\; +</span>\mathrm{<span\; class="notranslate">\; 0.2152</span>}}<span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 1.5</span>}<span\; class="notranslate">\; )</span>$

We use the electromagnetic full-wave algorithm (finite-difference time-domain algorithm) to perform electromagnetic simulation on the electronic bandgap structure composed of coplanar compact electronic bandgap units, thereby obtaining the stopband frequency of the electronic bandgap structure. We use the electromagnetic full-wave algorithm The electronic bandgap structure is optimized so that the stopband frequency of the electronic bandgap structure is equal to the upper limit operating frequency of the filter, thereby obtaining the size of the electronic bandgap unit.

Claims (1)

1, a kind of substrate integration wave-guide--electronic band gap band pass filter, comprise: two-sided being covered with respectively as end face, the end face metal patch on ground and ground metal paster (21,22) dielectric substrate (3), on dielectric substrate (3), be provided with substrate integration wave-guide, this substrate integration wave-guide is made up of 2 row metal through holes (1) at least, end face metal patch and ground metal paster (21,22) connect by plated-through hole (1), on the ground of dielectric substrate (3), be provided with the electronic band gap structure, on the end face of dielectric substrate (3), be provided with input (2) with output (5) and be connected with same substrate integration wave-guide respectively, it is characterized in that the electronic band gap structure is made up of the compact electronic band gap unit, isoplanar (4) by arrayed, have at least compact electronic band gap unit, 1 row isoplanar to be positioned on the ground of substrate integration wave-guide interior zone, remaining compact electronic band gap unit, isoplanar lay respectively at substrate integration wave-guide among the outside of the adjacent 2 row metal through holes of axis, the plated-through hole that is used to constitute substrate integration wave-guide lays respectively between each electronic band gap unit of compact electronic band gap unit, 2 row isoplanar.

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