Research On Millimeter Wave Interdigital Bandpass Filter Based On TSV

With the tremendous development of semiconductor technology,high-quality integrated passive devices(IPDs)based on TSV have gradually expanded to the millimeter wave field,which will greatly promote the integration of radio systems.Millimeter waves exhibit high transmission rates,narrow beams,and high reliability in high-speed wireless transmission.Passive components based on millimeter waves have higher requirements for small size and light weight.As one of the important components of RF front-end systems,the current bandpass filters mainly use two-dimensional microstrip line structures,which mainly have large dimensions and cannot meet the growing frequency band requirements.3D integration technology vertically penetrates the silicon substrate through Through Silicon Via(TSV)to achieve signal transmission between the upper and lower chips.It can achieve heterogeneous integration of different modules such as analog circuits,RF circuits,and logic circuits.It has the advantages of short latency,fast speed,low power consumption,and low quality factor.The bandpass filter based on TSV has the advantages of miniaturization and low loss at high frequencies,which can make up for the shortcomings of traditional interdigital bandpass filters and break through the technical bottlenecks they face.This article proposes four types of interdigital bandpass filters based on TSV structure,utilizing the miniaturization and low loss characteristics of TSV.The main work is as follows:1.Based on the coupling principle between interdigital resonators and the design principle of Chebyshev bandpass filters,a fifth order V-band wideband interdigital bandpass filter based on TSV is proposed.By converting the Chebyshev low-pass filter model to the Chebyshev bandpass filter,a uniformity impedance resonator is used as the main resonant unit of the interdigital bandpass filter.By implementing an ideal circuit model,the feasibility of an interdigital bandpass filter based on TSV structure is verified.Finally,through simulation verification of HFSS,a compact wideband interdigital bandpass filter in the V-band under TSV technology is obtained.The fractional bandwidth(FBW)center frequency f0 of the V-band fifth-order interdigital bandpass filter based on TSV is 63.5GHz,the fractional bandwidth(FBW)is 25%,the out of band suppression at 1.3f0 is greater than 50dB,the insertion loss is 1.1dB,and the return loss is 27.4dB.The size of the compact interdigital bandpass filter is only 0.83×0.53mm2(0.61 ×0.39λg2)。2.A seventh-order W-band interdigital bandpass filter based on TSV is proposed based on the coupling coefficient method and Chebyshev low-pass filter network.By combining the TSV technology with the coupling coefficient method,an improved method was proposed to improve the influence of parasitic inductance on the design process.The transformation from the Chebyshev low-pass filter model to the Chebyshev bandpass filter was completed,resulting in a wideband compact interdigital bandpass filter in the W-band of TSV technology.The fractional bandwidth(FBW)center frequency f0 of the W-band seven-order interdigital bandpass filter based on TSV is 85GHz,the fractional bandwidth(FBW)is 63%,the out of band suppression is greater than 80dB,the insertion loss is 1.3dB,and the return loss is 20dB.The size of the compact interdigital bandpass filter is only 0.50×0.34mm2(0.48×0.33λg2).3.Based on the coupling principle between interdigital resonators and the working principle of Stepped Impedance Resonators(SIR),a TSV based SIR interdigital bandpass filter is proposed adopt λ/4 As the main resonant unit,SIR achieves higher coupling strength under small impedance ratio.By fitting the curve of coupling coefficient and spacing between resonant units,the design accuracy is improved and the number of iterations is reduced.The SIR interdigital bandpass filter based on TSV has a compact size and far parasitic passband,and exhibits excellent fractional bandwidth and out of band suppression characteristics.The fractional bandwidth(FBW)center frequency f0 of the W-band seven-order interdigital bandpass filter based on TSV is 98.5GHz,the fractional bandwidth(FBW)is 40%,,the insertion loss is less than 1.3dB,and the reflection in the passband is better than 30dB.The size of the compact SIR interdigital bandpass filter is only 0.24×0.7mm2(0.28×0.79λg2).4.Based on the working principles of SIR and interdigital bandpass filters,a TSV based SIR dual interdigital bandpass filter is proposed.By folding the SIR resonant unit,further reducing the size,and achieving greater coupling strength through a lower SIR impedance ratio,the studied filter has a small size,wide passband,and high spurious frequency.The center frequency of the SIR dual interdigital bandpass filter based on TSV is 57GHz,the fractional bandwidth(FBW)is 10%,the insertion loss is less than 1.3dB,and the reflection in the passband is better than 22dB.The size of the millimeter wave SIR dual interdigital bandpass filter based on TSV is 0.32×0.98mm2(0.21×0.79λg2).