Ka-band MMIC SPDT Switch Based On GaN HEMT

As the third generation semiconductor material, Ga N wide band-gap semiconductor has advantages of high thermal conductivity, high breakdown voltage, high mobility, high temperature resistance, radiation resistance and so on. Especially, they are suitable for application in millimeter-wave digital radar systems. Transmitter and Receiver(T/R) module is the core component of the radar system, and its performance has a direct impact on the development of radar system. Based on our project team recently has designed Ka-band Ga N high electron mobility transistor(HEMT) power amplifier monolithic microwave integrated circuit(MMIC), this paper discusses the research and design of Ka-band Ga N HEMT single pole double throw(SPDT) switch MMIC in order to design a T/R module MMIC. The main research contents include:At first, this paper introduces the physical structure and working principle of Ga N HEMT which is the active components in the power amplifier. Complete the modeling and simulation of the passive devices, such as spiral inductor, MIM capacitance, by using HFSS software, getting the relationship between the value of the device, quality factor and the physical size.On the basis of above research, completing the design of Ka-band Ga N HEMT monolithic microwave integrated SPDT switch. Then starting the design of the SPDT switch topology structure through ADS software. This switch circuit uses parallel symmetrical network to improve the isolation; uses parallel resonant inductor to reduce the insertion loss and uses impedance matching to expand bandwidth. Then completing the design of the layout topology structure. Finally, the simulation of the layout and the simulation of the electromagnetic field are carried out.Unfortunately, failed to tape out real product because of the limited time. The parameters can be reached according to simulation result: In band 30GHz~40GHz, the insertion loss of this MMIC switch is less than 2 d B; the isolation is more than 25 d B; the capability of power is higher than 7.94w; the switching time is less than 1 ns and the return loss is more than 22 d B.