Research On Ultra-wideband High-gain Millimeter Wave Antenna-in-package

Microstrip patch antennas have been widely studied and used due to their advantages of miniaturization,light weight,and easy integration.With the low-frequency spectrum resources being used up,experts and scholars have begun to focus their research on the millimeter wave frequency band.Therefore,this thesis takes the millimeter-wave packaging technology of the microstrip antenna as the research topic,and focuses on exploring a broadband impedance matching realization technology,and uses a metal back cavity to improve the antenna's radiation performance.The main work of this thesis is as follows:1.A research on the embedded metal sleeve structure to realize the impedance matching of the ultra-wideband antenna has been conducted.With the ultra-wideband impedance matching control structure,an ultra-wideband microstrip antenna that works in the S-band and C-band was designed.The metal sleeve structure is added on the coaxial position of the feeding probe to realize the impedance matching of the antenna in the ultra-wideband range.The simulation results show that the proposed antenna achieves a relative impedance bandwidth of about 50%(S11<-10 dB)on the 3 GHz-5 GHz frequency band.The achievable maximum gain of the antenna is 9.68 dBi.2.A study on the improved embedded impedance control structure to making it suitable for low-temperature co-fired ceramics,high-density interconnection PCB and other packaging antenna processes has been carried out.Based on the impedance control structure and a"convex"type metal back cavity,an ultra-wideband high gain millimeter-wave antenna-in-package has been built.The radiating patches and metal back cavity of the antenna are both"convex"-shaped,and are fed by differential feedings.The metal sleeve structures are placed at the coaxial position of the feeding probe to achieve impedance matching of the antenna in the ultra-wideband range.The"convex"-shaped metal back cavity and the strip line play a role in improving the antenna's radiation characteristics.The simulation results show that the antenna has an impedance bandwidth of about 101.6%,the frequency band covers31.5 GHz-92.5 GHz(S₁₁<-10 dB),and the impedance bandwidth is 61 GHz;the antenna has a stable radiation pattern on the working frequency band,and the maximum gain is 11.6 dBi,its3-dB gain bandwidth is 56.3 GHz-92.5 GHz with the 3-dB gain bandwidth of 36.2 GHz.3.A further research on the effect of the back cavity on impedance and radiation pattern has been conducted,the mechanism of optimizing the shape of the back cavity to achieve more stable gain performance has been studied,and a rectangular and octagonal-shaped back cavity millimeter-wave antenna-in-package have been designed to explore the influence of the shape of the back cavity on the performance of the antenna radiation.Both of the antennas'size have been adjusted to work on the bandwidth around 20 GHz to 60 GHz.The simulation results show that the impedance bandwidth of the rectangular cavity-backed antenna is 22.2GHz-64.5 GHz,the maximum gain is 11.7 dBi,and the 3-dB gain bandwidth is 36.5 GHz;the working bandwidth of the octagonal cavity-backed antenna is 22.5 GHz-67.8 GHz,the bandwidth is 45.3 GHz,the relative impedance bandwidth is 100.3%,the maximum gain is12.3 dBi,and the 3-dB gain bandwidth is 33.9 GHz.Finally,an integrated ultra-wideband millimeter wave packaged antenna is designed in combination with an ultra-wideband differential feeding network.The integrated ultra-wideband millimeter-wave antenna-in-package maintains the similar characteristics of the octagonal cavity-backed antenna.The impedance bandwidth of the integrated ultra-wideband millimeter-wave antenna-in-package ranges from 23.4 GHz to 66.5 GHz,the relative impedance bandwidth is95.9%,and the maximum gain is 11.56 dBi,and its 3-dB gain bandwidth reaches 28.6 GHz.