| Millimeter wave(mm-wave)provides the possibility to realize ultrahigh speed wireless communication systems because of its abundant spectrum resources.Among them,the planned V-band(59-64 GHz)is widely used in short-range high-speed wireless communication systems due to its advantages of free authorization and high attenuation.E-band(71-76GHz/81-86GHz)is also planned for satellite-to-ground communication and commercial microwave communication links because it is in the atmospheric attenuation window and has low atmospheric loss.Therefore,the research on V-band and E-band RF components is of great significance for promoting wireless network construction and realizing the strategy of space-air-ground integration.Based on these backgrounds and requirements,the author has carried out a series of researches on filters,filtering characteristics components,and packaging structures applicable to mm-wave high-speed wireless communication systems for different application scenarios and communication system architectures,mainly including the following research contents:1.For the E-band superheterodyne communication system architecture,three bandpass filters with miniaturization and low insertion loss(IL)characteristics are designed to improve RF link performance.Firstly,a multilayer gap waveguide structure is used to reduce the device size,and a miniaturized low IL bandpass filter is designed based on cross coupling topology.The measured results show that its passband is 70.776.6 GHz,the IL in the flat passband is only 0.45±0.16 dB,and the orthographic projection area is only(2.05 × 1.27)λ;Secondly,based on a multimode cavity,a miniaturized filter that is easy to process is designed and combined with a quasi-extracted pole cavity to suppress its harmonics.It only has seven structural parameters.The measured results show that its passband is 80.6-84.1 GHz,the IL in a flat passband is only 0.6 ± 0.12 dB,and the volume is only(1.82±1.88±0.71)λ;Finally,a miniaturized bandpass filter with high out of band rejection is designed using a cavity with a non-resonating mode and a central tuning nail to introduce multiple operating modes.The measured results show that its passband is 73.9676.14 GHz,and the IL in a flat passband is only 0.6±0.15 dB,with two transmission zeros at 71.55 GHz and 73.31 GHz,with a low-frequency side suppression level better than 60 dB.2.Aiming at the frequency division duplex and frequency division multiplexing communication system architecture of E-band and V-band,and based on the specific frequency band division,three diplexers or multiplexers with high isolation or miniaturization characteristics are designed to improve the transmission rate and ensure the communication quality.Firstly,two fifth-order bandpass filters are designed based on the cavity with non-resonant mode,and a diplexer with high isolation is designed by combining the T-junction power dividing unit.The measured results show that the IL of channel 1 is about 1.35 dB in the 71-73 GHz band,and the IL of channel 2 is about 1.5 dB in the 74-76 GHzband.Under the condition of 1 GHz interval bandwidth,the channel isolation of 65 dB is realized.Secondly,the mushroom-type EBG structure with high rejection is applied to the design of the diplexer.Based on the proposed secondary frequency selection topology,a diplexer with high isolation is designed.The simulation results show that the passbands are 58.5-61.5 GHz and 63.5-66.5 GHz,respectively.The ILs are less than 1.15 dB and 1.19 dB,respectively,and the channel isolation is greater than 37 dB.Finally,four band-pass filters are designed based on the multi-mode cavity,and a miniaturized quadruplexer is designed by combining the manifold topology with miniaturization characteristics.The measured results show that the IL of channel 1 is about 0.6 dB in the 71-73 GHz band.The IL of channel 2 is about 0.7 dB in the 74-76 GHz band.The IL of channel 3 is about 0.6 dB in the 81-83 GHzband.The IL of channel 4 in the 84-86 GHz band is about 0.6 dB.3.Aiming at the integration and miniaturization requirements of communication systems,the most commonly used filters and their connected components in superheterodyne communication systems are integrated or miniaturized to improve the stability and portability of communication systems.Firstly,an H-plane CPW-waveguide probe is designed.Combined with the series EBG structures,a band-stop packaging structure with adjacent harmonic suppression is designed for the frequency multiplier used in the E-band.The simulated results show that it can accurately suppress the eighth and tenth harmonics,and the IL in the passband is only 1 dB.Secondly,aiming at the duplex and power combining requirements of the system,based on the principle of the hybrid-coupled multiplexer,an H-plane transition structure is used for amplifier packaging design,and a packaging transition structure with duplex and power combining characteristics is designed.The measured results show that the passbands of the back-to-back structure are 70.9576.2 GHz and 80.92-86.25 GHz,respectively.The maximum ILs in the passband are 2.26 dB and 2.42 dB,respectively,and the channel isolation is better than 70 dB.Finally,a miniaturized circularly polarized filtering feed is designed for the V-band time division duplex communication system.The simulated results show that the operating frequency of the filtering feed horn is 59-64 GHz,the gain is 10.5±0.5 dBic,and the axial ratio is less than 1 dB. |
