阅读说明：本技术 一种片上毫米波带通滤波器 (On-chip millimeter wave band-pass filter ) 是由 戈泽宇 陈浪 陈力生 于 2021-06-30 设计创作，主要内容包括：本发明公开了一种片上毫米波带通滤波器。包括：中心抽头环形谐振器、接地屏蔽层、第一MIM电容器与第二MIM电容器、输入馈线和输出馈线；中心抽头环形谐振器呈曲折线形状弯曲排列,一端包括一个弯曲端,另一端包括两个弯曲端,通过四组平行的指位于弯曲端两侧形成,滤波器输入端与输入馈线相连,输入馈线的另一端与中心抽头环形谐振器的一侧的指相连；滤波器输出端与输出馈线相连,输出馈线的另一端与中心抽头环形谐振器的另一侧的指相连；接地屏蔽层位于中心抽头环形谐振器外围。该滤波器的优点在于曲折线型中心抽头环形谐振器可以有限的减小片上毫米波带通滤波器的面积,而位于馈线下方的两个MIM电容合理利用多层结构,进一步的缩减芯片的面积。(The invention discloses an on-chip millimeter wave band-pass filter. The method comprises the following steps: a center-tapped ring resonator, a ground shield, first and second MIM capacitors, an input feed line, and an output feed line; the center-tap ring resonator is arranged in a zigzag curve shape in a bending way, one end of the center-tap ring resonator comprises a bending end, the other end of the center-tap ring resonator comprises two bending ends, the two bending ends are formed by four groups of parallel fingers positioned on two sides of the bending end, the input end of the filter is connected with the input feeder line, and the other end of the input feeder line is connected with the finger on one side of the center-tap ring resonator; the output end of the filter is connected with an output feeder line, and the other end of the output feeder line is connected with a finger on the other side of the center tap ring resonator; the ground shield is located around the center-tapped ring resonator. The filter has the advantages that the area of the millimeter wave band-pass filter on the chip can be reduced in a limited way by the zigzag type center tap ring resonator, and the multilayer structure is reasonably utilized by the two MIM capacitors positioned below the feeder line, so that the area of the chip is further reduced.)

1. The utility model provides a millimeter wave band-pass filter on chip which characterized in that realizes through predetermineeing the layer structure, includes: a center-tapped ring resonator, a ground shield, first and second MIM capacitors, an input feed line, and an output feed line;

the center-tap ring resonator is arranged in a zigzag curve shape in a bending mode and comprises four groups of parallel fingers, the fingers on two sides are respectively connected with the adjacent fingers at the same side to form a bent end, the finger in the middle is connected at the other end to form a bent end, the input end of the filter is connected with an input feeder line, and the other end of the input feeder line is connected with the finger on one side of the center-tap ring resonator; the output end of the filter is connected with an output feeder line, and the other end of the output feeder line is connected with a finger on the other side of the center tap ring resonator; the grounding shielding layer is positioned at the periphery of the center-tapped ring resonator, the bent end of the center-tapped ring resonator, which is positioned at one end of only one bent end, is connected with the grounding shielding layer, and the two MIM capacitors are respectively positioned below the input feeder line and the output feeder line.

2. The bandpass filter according to claim 1, wherein the center-tapped ring resonator comprises a first layer transmission line and a second layer transmission line, the first layer transmission line is defined by a metal layer TM2 of a predetermined layer structure, the second layer transmission line is defined by a metal layer TM1, and the finger ends of the two side fingers of the first layer transmission line and the second layer transmission line have via holes through which the first layer transmission line and the second layer transmission line are connected.

3. A bandpass filter according to claim 2, characterized in that the fingers on both sides of the transmission line of the first layer are connected to an input feed line and an output feed line.

4. The bandpass filter according to claim 2, wherein the ground shield is connected through the bent end of the transmission line of the second layer.

5. The bandpass filter according to claim 1 or 4, wherein the ground shield is a multilayer structure, with the metal layer TM2 forming the uppermost layer, the metal layer TM1 forming the second layer of the ground shield, the metal layer M5 forming the third layer of the ground shield, and so on, the metal layer M1 forming the last layer of the ground shield.

6. The bandpass filter according to claim 1 or 4, wherein metal layer TM1 forms an upper layer of the MIM capacitor and metal layer M5 forms a lower layer of the MIM capacitor.

7. The bandpass filter according to claim 2, wherein the length of each finger is 160 microns, the horizontal distance between adjacent fingers is 10 microns, and the vertical distance of metal layer TM1 and metal layer TM2 is 2.8 microns.

Technical Field

The invention relates to the technical field of filters, in particular to an on-chip millimeter wave band-pass filter.

Background

The millimeter wave band generally refers to a frequency band of 30GHz to 300 GHz. The development of the millimeter wave system is also a trend of future communication development, and as low-frequency spectrum resources are increasingly deficient, a millimeter wave frequency band still has a large development space, and in addition, the millimeter wave design has the advantages of small size, light weight, interference resistance and the like, the millimeter wave system has great development potential in the field of future wireless communication. This trend of development also inevitably leads to rapid development of millimeter wave filters. On the other hand, the design of the on-chip band-pass filter based on the silicon-based process also draws wide attention at home and abroad, and the design of the on-chip filter needs to be balanced continuously, no matter in terms of noise, bandwidth, linearity or chip size, so that it is also a sharp challenge to design an on-chip band-pass filter with good in-band flatness, low insertion loss and high stop-band attenuation.

The existing filter technology has the following defects: designs based on conventional ring resonators have been successful in achieving on-chip design and have excellent performance, but the chip size of the filter is relatively large. In view of manufacturing costs, it is always desirable to minimize the physical size of the on-chip filter. Under this prerequisite, in order to effectively reduce the physical size of the filter, a notch-based design method has been widely adopted. For example, broadside-coupled meander-line resonator-based designs achieve minimum physical dimensions. However, this approach provides only a limited amount of attenuation over a small bandwidth of the stop band, with a large compromise in performance.

Disclosure of Invention

The present invention is directed to solving at least one of the problems of the prior art or the related art.

Therefore, the invention aims to provide an on-chip millimeter wave band-pass filter with an MPG element based on a coupled line structure.

In order to achieve the purpose, the technical scheme of the invention provides a method.

The utility model provides a millimeter wave band-pass filter on chip, realizes through predetermineeing the layer structure, includes: a center-tapped ring resonator, a ground shield, first and second MIM capacitors, an input feed line, and an output feed line;

the center-tap ring resonator is arranged in a zigzag curve shape in a bending mode and comprises four groups of parallel fingers, the fingers on two sides are respectively connected with the adjacent fingers at the same side to form a bent end, the finger in the middle is connected at the other end to form a bent end, the input end of the filter is connected with an input feeder line, and the other end of the input feeder line is connected with the finger on one side of the center-tap ring resonator; the output end of the filter is connected with an output feeder line, and the other end of the output feeder line is connected with a finger on the other side of the center tap ring resonator; the grounding shielding layer is positioned at the periphery of the center-tapped ring resonator, the bent end of the center-tapped ring resonator, which is positioned at one end of only one bent end, is connected with the grounding shielding layer, and the two MIM capacitors are respectively positioned below the input feeder line and the output feeder line.

Furthermore, the center tap ring resonator comprises a first layer transmission line and a second layer transmission line, the first layer transmission line is formed by carving a metal layer TM2 of a preset layer structure, the second layer transmission line is formed by carving a metal layer TM1, the finger ends of the two sides of the first layer transmission line and the second layer transmission line are provided with through holes, and the first layer transmission line and the second layer transmission line are connected through the through holes.

Further, the fingers on both sides of the first layer transmission line are connected with an input feeder line and an output feeder line.

Further, the bandpass filter according to claim 2, wherein the second transmission line is connected to the ground shield via the bent end of the second transmission line.

Further, the bandpass filter according to claim 1 or 4, wherein the ground shield layer has a multi-layer structure, the metal layer TM2 forms the uppermost layer, the metal layer TM1 forms the second layer of the ground shield layer, the metal layer M5 forms the third layer of the ground shield layer, and so on, the metal layer M1 forms the last layer of the ground shield layer.

Further, metal layer TM1 forms the upper layer of the MIM capacitor and metal layer M5 forms the lower layer of the MIM capacitor.

Further, the length of each finger is 160 microns, the horizontal distance between adjacent fingers is 10 microns, and the vertical distance between metal layer TM1 and metal layer TM2 is 2.8 microns.

The invention has the following beneficial effects:

the invention adopts a 0.13 mu m (Bi) -CMOS process and uses a Cadence 3-D EM tool for design optimization. The minimum allowable gate length is 0.13 μm, so that the precision of +/-1% can be realized, and the area of the final chip is 0.74 multiplied by 0.196mm². The center frequency of the invention is 28GHz, the corresponding insertion loss is 1.9dB, the bandwidth with the Return loss less than-10 dB is 21.5-35GHz, and the out-of-band rejection reaches at least 20dB at 2 harmonic waves and higher frequencies;

additional aspects and advantages of the invention will be set forth in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention.

Drawings

FIG. 1 shows a schematic diagram of the structure of an on-chip millimeter wave band-pass filter of the present invention;

FIG. 2 is a schematic diagram showing a preset layer structure of an on-chip millimeter wave band-pass filter;

FIG. 3 shows the structure of the metal layer TM2(a) and the metal layer TM1(b) for designing the on-chip millimeter wave band-pass filter of the present invention;

FIG. 4 is a graph showing EM simulation results of varying different MIM capacitance values to affect S11 and S21 parameters;

fig. 5 shows a graph of EM simulation results of the effect of changing the lengths of different metal wires on the parameters S11 and S21.

Detailed Description

In order that the above objects, features and advantages of the present invention can be more clearly understood, a more particular description of the invention will be rendered by reference to the appended drawings. It should be noted that the embodiments and features of the embodiments of the present application may be combined with each other without conflict.

In the following description, numerous specific details are set forth in order to provide a thorough understanding of the present invention, however, the present invention may be practiced in other ways than those specifically described herein, and therefore the scope of the present invention is not limited to the specific embodiments disclosed below.

Fig. 1 shows a schematic structural diagram of an on-chip millimeter wave band-pass filter according to the present invention. The method comprises the following steps: a center-tapped ring resonator 1, a ground shield 5, first and second MIM capacitors 3 and 6, an input feed 4, and an output feed 2; wherein the filter input is connected to an input feed 4 and the other end of the input feed 4 is connected to the centre-tapped ring resonator 1. The output end of the filter is connected with an output feeder 2, and the other end of the output feeder 2 is connected with a center tap ring resonator 1. The grounding shielding layer 5 is positioned at the periphery of the center-tap annular resonator, the center-tap annular resonator is arranged in a zigzag curve shape in a bending way, one end of the center-tap annular resonator comprises a bending end, the other end of the center-tap annular resonator comprises two bending ends 7, the bending ends are formed by four groups of parallel fingers 8, the input end of the filter is connected with an input feeder line, and the other end of the input feeder line is connected with the finger at one side of the center-tap annular resonator; the output end of the filter is connected with an output feeder line, and the other end of the output feeder line is connected with a finger on the other side of the center tap ring resonator; the grounding shielding layer is positioned at the periphery of the center-tapped ring resonator, the bent end of the center-tapped ring resonator, which is positioned at one end of only one bent end, is connected with the grounding shielding layer, and the two MIM capacitors are respectively positioned below the input feeder line and the output feeder line.

Fig. 1 is combined with fig. 2 and fig. 3, specifically, the center-tapped ring resonator includes a first layer transmission line and a second layer transmission line, the first layer transmission line is defined by a metal layer TM2 of a preset layer structure, the second layer transmission line is defined by a metal layer TM1, finger ends of two side fingers of the first layer transmission line and the second layer transmission line are provided with via holes 9, and the first layer transmission line and the second layer transmission line are connected by the via holes 9.

The first layer transmission line comprises four fingers which are parallel, the fingers on the outer sides of the four fingers are respectively connected with the adjacent middle fingers, the two outer ends of the two middle fingers are connected to form a bent end, the second layer transmission line also comprises four fingers which are parallel, the fingers on the outer sides of the four fingers are respectively connected with the adjacent middle fingers, and the two outer ends of the two middle fingers are connected to form a bent end and correspond to each other up and down in structure.

The bent end of the second layer transmission line of the center-tapped ring resonator is connected with the grounding shielding layer 5 after being protruded, and fingers on two sides of the first layer transmission line are connected with the input feeder line and the output feeder line. The two MIM capacitors are respectively positioned below the input feeder line and the output feeder line. The center-tapped ring resonator is formed by patterning a metal layer TM2 with a preset layer structure, the MIM capacitor is located between the metal layer TM1 and the metal layer M5, and the input feed line and the output feed line are located on the metal layer TM 2. The line width of the center-tapped resonator with MIM-capacitance value of 0.2pF. is 4 microns for a total of 8 fingers, of which 4 fingers are implemented with top metal layer TM2 and 4 others with metal layer TM 1. The length of each finger is 160 microns, the horizontal distance between each finger is 10 microns, and the vertical distance between metal layer TM1 and metal layer TM2 is 2.8 microns.

The grounding shielding layer is of a multilayer structure, the uppermost layer is formed on the metal layer TM2, the metal layer TM1 forms the second layer of the grounding shielding layer, the metal layer M5 is the third layer of the grounding shielding layer, and the like, the metal layer M1 forms the last layer of the grounding shielding layer.

Fig. 2 shows a schematic diagram of a preset layer structure of the on-chip millimeter wave band-pass filter according to the present invention. As shown in fig. 2, the preset layer structure includes: the metal layer TM2, the metal layer TM1, the metal layer M5, the metal layer M4, the metal layer M3, the metal layer M2, the metal layer M1 and the silicon substrate layer are sequentially arranged at the bottom of the first preset layer structure; silicon dioxide layers are arranged between the metal layer TM2 and the metal layer TM1, between the metal layer TM1 and the metal layer M5, between the metal layer M5 and the metal layer M4, between the metal layer M4 and the metal layer M3, between the metal layer M3 and the metal layer M2 and between the metal layer M2 and the metal layer M1; the metal-insulator-metal layer MIM is comprised of the metal layer TM1, metal layer M5, and a silicon dioxide layer therebetween. The metal layer TM2, the metal layer TM1, the metal layer M5 and the metal layer M2 are all aluminum metal layers. The thickness of the metal layer TM2 is 3 μm; the thickness of the metal layer TM1 is 2 μm; the metal layer M5, the metal layer M4, the metal layer M3 and the metal layer M2 are all 0.45 mu M; the thickness of the metal layer M1 is 0.4 μ M; the thickness of the silicon substrate layer is 200 μm; the distance between the lower surface of the metal layer TM2 and the upper surface of the metal layer TM1 is 3 μm; the distance between the lower surface of the metal layer TM1 and the upper surface of the metal layer M2 is 4 μ M; and the distance between the lower surface of the metal layer M2 and the upper surface of the silicon substrate layer is 2.07 μ M. The pre-set layer structure of the present invention is designed and implemented in standard 0.13- μm (bi) -CMOS technology.

In this embodiment, by setting the thickness of each metal layer of the preset layer structure and the thickness of the silicon substrate layer to fixed values, it is possible to achieve better miniaturization design of the bandpass filter of the present invention.

For a clearer understanding of the structure of the center-tapped ring resonator, fig. 3 shows a schematic diagram of the structure of the metal layer TM2(a) and the metal layer TM1(b) of the on-chip millimeter wave band-pass filter based on the meander-line type center-tapped ring resonator; the metal layer TM1 includes two vias, input and output end feeders, and a transmission line, and the transmission line in the metal layer TM1 is connected to the metal layer TM2 through the vias, and is connected to the ground shield layer at the metal layer TM 2. The transmission lines in metal layer TM2 and metal layer TM2 together constitute a center-tapped ring resonator. In addition, the metal layer TM2 is the uppermost layer of the ground shield, the input-output feed line, and the center-tap resonator. Metal layer TM1 is the second layer of the ground shield and the upper layer of the MIM capacitor. Metal layer M5 is the third layer of the ground shield and the lower layer of the MIM capacitor. In addition, the grounding shielding layer is formed by stacking a plurality of metal layers, and the M5-M1 layers have simple structures of the grounding shielding layer, which is not described more here. According to the invention, by utilizing a multi-layer result, the MIM capacitor is placed below the input/output feeder line, and the center tap ring resonator is formed by utilizing the bent line structure, so that the area of the on-chip filter is effectively reduced to the minimum, an additional transmission pole can be generated by utilizing the center tap ring resonator and the two MIM capacitor structures, flexible balance can be carried out between in-band flatness and passband bandwidth by simply adjusting the position of the transmission pole, faster roll-off can be realized in a low-frequency stop band, and excellent stop band performance is provided.

The filter has the advantages that the meander line type center tap ring resonator can reduce the area of the millimeter wave band-pass filter on the chip in a limited way, the two MIM capacitors positioned below the feeder line reasonably utilize a multilayer structure, the area of the chip is further reduced, and the resonator and the MIM capacitors can be used for carrying out flexible balance between in-band flatness and passband bandwidth, so that bandwidth adjustment can be carried out very flexibly, and meanwhile, excellent stop band performance is provided, and the roll-off of an upper transition band and a lower transition band is improved.

Fig. 4 shows a graph of EM simulation results for the effect of varying different MIM capacitance values on the S11, S21 parameters.

The results of the S-parameter simulation of the filter are given in fig. 4 when the capacitance is adjusted from 0.1pF to 0.2pF, the step being 0.05 pF. When the capacitance changes from small to large, the center frequency of the filter shifts to low frequencies.

Fig. 5 is a graph showing the EM simulation results of the influence of changing the lengths of different metal wires on the parameters S11 and S21. The longer the length of the wire, the lower the center frequency.

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.