Development of High Performance HTS Filter for CDMA Mobile Communication System
This paper presents a high performance high temperature superconducting(HTS) filter with a 6 MHz bandwidth at 832 MHz.We use a compact half wavelength dual spiral resonator in the design process.The linewidth of the resonator is 80 mm,and the gap between tracks is 80 mm.Thus,a twelve pole HTS filter with a size of only 41.4 mmx14 mm is realized on an MgO substrate.The EM simulations show that the filter response is insensitive to the variations of the substrate parameters and the simulation cell size.The fabrication process was carefully carried out,and the untuned measured results of the filter match well with the simulated ones and show high performances.The passband insertion loss is less than 0.36 dB,the return loss is better than 15.6 dB,and the out of band rejection is higher than 100 dB.