A High Isolation Switch Circuit Design Based on HTCC
Switch circuit based on the switch chip is the basic unit of radio frequency front-end circuits,which can achieve ra-dio frequency signal on and off and is widely used in low-power radio frequency signal transmission.In this paper,a high isolation switch circuit based on the high-temperature co-fired ceramics substrate and the cascaded isolation cavity,formed by cascaded switch chips as the basic circuit is designed.The frequency is 6 GHz~15 GHz and the isolation index is 60 dB.The switch circuit consists of a limiter chip and two absorption type gallium arsenide single-pole single throw switches,which are assembled in two adjacent isolation cavity structures,and transitioned to a symmetrical stripline transmission structure inside the substrate through the coaxial-like vertical transmission,supplemented by ground holes on both sides to achieve electromagnetic shielding.The elec-tromagnetic field modeling and simulation of the switch circuit show that it has good transmission and isolation characteristics.After the radio frequency front-end circuit is manufactured,the switch circuit is assembled and tested.The test results are consistent with the modeling and simulation results,verifying the high isolation switch circuit design in this paper.