| As wireless communication system and radar system have a higher demand for the operating bandwidth and data rate,millimeter wave technology has received widespread attention from academic and industrial world.As compared with the microwave frequency band,millimeter wave is so rich in resource that it can solve the problem of shortage in resource of frequency of microwave frequency band.Moreover,the operating wavelength of millimeter wave is shorter,which helps to improve the system’s integration and realize the miniaturization and low-cost design.The successful research and development of millimeter wave radio frequency front-end is the key to make millimeter wave technology practical.Because of the development of silicon-based integrated circuit manufacturing process,the millimeter wave frequency band has been covered by the intrinsic frequency fT of transistors.At present,many efforts have been made in the research of the silicon-based millimeter wave radio frequency system and some results have been achieved by research teams at home and abroad,but there are still problems in the design of the millimeter-wave radio frequency front-end.Therefore,in this thesis,with the silicon-based millimeter wave radio frequency front-end key technology as the research objective,ultra-wideband radio frequency reconfigurable filter,miniaturized through-wall radar antenna,silicon-based millimeter wave reflective array are carefully and thoroughly investigated.The main research result and innovation are as follows:An novel 2-18GHz RF reconfigurable filter bank is designed based on 130nm SiGe BiCMOS process.The filter bank is composed of a high-order filter unit and a microwave radio frequency switch.The high-order filter unit is composed of multiple active Q-enhanced LC filters in series or parallel,whose operating frequency and Q value are controlled by voltage and can be adjusted continually.By adjusting the mismatch between one filter with another(Q value and frequency point),the notch wave effect outside of the band is generated,improving the out-of-band suppression ability and the operating bandwidth and in-band flatness can meet the design requirement.The microwave radio frequency switch is the double-pole four-throw(DP4T)structure and adopts the serial-parallel MOS tube mode,which reduces the insertion loss and improves the isolation between ports.The simulation results show that the maximum insertion loss of the RF switch is 3.3dB in the operating frequency band of 0-20GHz,the isolation between ports is over 25dB,and the input 1dB compression point is 12dBm.Finally,a reconfigurable filter bank with an operating frequency range of 2-18GHz is constructed by the above high-order filter unit and radio frequency switch.The measured results of tape-out show that within the operating frequency band of this filter bank its operating frequency points can be adjusted continually,and the 3dB bandwidth over 0.1-1GHz,the insertion loss is approximately 0dB,the in-band ripple is less than 1.5dB,in 2-6.5GHz,the out-of-band suppression at 0.2f0 is greater than 40dB,in 6.5-18GHz and the out-ofband suppression at 0.15f0 is greater than 30dB,the range of input 1dB compression point and noise figure are 0.3～2.5dBm and 20～25dB,respectively.The reconfigurability of operating bandwidth,out-of-band suppression,and in-band flatness enables the filter bank to meet the design requirements of ultra-wideband reconfigurable RF front-endsA miniaturized ultra-wideband gain-enhanced Vivaldi transceiver antenna is designed,which is applied in the portable through-wall radar.Based on traditional Vivaldi antenna,it keeps the entire width unchanged and improves the in-band radiation performance of the traditional ones by adding rectangle branches regularly distributed along the radiation opening.The test results show that the gain-enhanced Vivaldi antenna has a 4-8GHz operating bandwidth,the in-band 3dB beamwidth is less than 67°,the gain is approximately 8.3dBi,and the gain fluctuation in the operating frequency band is less than 1.5dB.By applying the traditional Vivaldi and enhanced Vivaldi antennas to the through-wall radar system,the test results in different detection scenarios show that the radar system with gain-enhanced Vivaldi antenna features longer detection distance and better angle resolution as compared with traditional one.Therefore,the gain-enhanced Vivaldi antenna’s good far-field radiation property and small size enable it to act as the transceiver antennas of various portable radio frequency systems.Based on TSMC 28nm CMOS process,a 140GHz reflective array antenna with beam scanning capability is designed,which is composed of a primary feed and a reflection front.In order to obtain a circularly symmetrical radiation far field on the reflecting array and improve the radiation efficiency of the reflecting array,a dual-mode conical horn is used as the primary feed.The electromagnetic simulation results show that the maximum gain of the horn antenna is 14.7dBi,the 10dB beam width is 54°,the cross polarization of the main radiation direction is less than-47dB,the radiation far-field E-plane and H-plane pattern basically coincide,and the radiation far-field has better circularly symmetrical.The reflection unit adopts a dual resonant varactor loaded structure.The electromagnetic and circuit co-simulation shows the unit reflection phase changes beyond 380° within the variable capacitance range of 15～25fF,and the return loss is less than 1.8dB.A 20×20 reflective array antenna was constructed by using the feed horn and the reflecting unit in the forward feed mode.The simulation results show that the maximum gain of the array system is 26.55dBi,the radiation efficiency is 41%,and it has the beam scanning capability within the 0～360°azimuth angle and the ±45°vertical angle.The capability of high gain and wide beam scanning enable the array antenna system to meet the application requirements of millimeter wave wireless communications,radar detection and other millimeter wave radio frequency systems. |
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