Compact and high density integrated design with high isolation for S-band up-conversion system

A compact and high density integrated design with high isolation for S-band up-conversion system is presented in this paper. The system has two phase locked loop(PLL) frequency sources which provide local oscillator(LO) signals for frequency conversion. In order to realize a high isolation design, the circuits of two PLL and mixer were divided into three independent cavities through a ‘T’ shape crosser. Base on the techniques of vertical via and inner route for PCB multilayer, almost all of the power distribute network was emdedded into inner layer, and the system layout realized a compact and high density design at the principle of shortest RF route. A transition structure of CPWG-SL-CPWG was put forward to interconnect the LO signals which can decline the EM couple. The size of the system board is 14.3mm*15.2mm*1.3mm, which is much smaller than a traditional product. The isolation between two LO from RF output is 82.6 dB, which agree with the simulation well.