Design of a narrowband HTS filter at 7.4-GHz with improved upper-stopband performance

Abstract This paper presents a high-temperature superconducting filter at 7.42 GHz with an improved upper-stopband performance. U-type stepped-impedance resonators are used to relocate the spurious frequency and realize wide stopband response. The compact resonators also reduce the filter size and push away the housing box resonant frequencies. Open stubs are introduced at the midpoints of the resonators to provide additional transmission zeros, which can improve both the band-edge steepness and the out-of-band rejection of the upper stopband. As a result, the spurious response of the filter is relocated to above 18 GHz, and the out-of-band rejection is higher than 70 dB.

[1]  J. Laskar,et al.  A low phase noise X-band MMIC GaAs MESFET VCO , 2000 .

[2]  Qing-Xin Chu,et al.  Design of UWB Bandpass Filter Using Stepped-Impedance Stub-Loaded Resonator , 2010, IEEE Microwave and Wireless Components Letters.

[3]  Bin Wei,et al.  Design of a novel HTS open-loop SIR filter with the relocation of its second passband , 2007 .

[4]  Jia-Sheng Hong,et al.  A high-temperature superconducting filter for future mobile telecommunication systems , 2005, IEEE Transactions on Microwave Theory and Techniques.

[5]  F. Huang,et al.  Superconducting spiral filters with quasi-elliptic characteristic for radio astronomy , 2005, IEEE Transactions on Microwave Theory and Techniques.

[6]  W. Menzel,et al.  Compact microstrip bandpass filter with two transmission zeros using a stub-tapped half-wavelength line resonator , 2003, IEEE Microwave and Wireless Components Letters.

[7]  Sheng Luo,et al.  A high-performance ultra-narrow bandpass HTS filter and its application in a wind-profiler radar system , 2006 .

[8]  Kaixue Ma,et al.  A Wideband and High Rejection Multimode Bandpass Filter Using Stub Perturbation , 2009, IEEE Microwave and Wireless Components Letters.

[9]  Robert B. Hammond,et al.  Superconducting microwave filter systems for cellular telephone base stations , 2004, Proceedings of the IEEE.

[10]  Junjie Li,et al.  A 23 GHz high-temperature superconducting microstrip filter for radio astronomy , 2009 .

[11]  Jia-Sheng Hong,et al.  Microstrip filters for RF/microwave applications , 2001 .

[12]  Sang-Won Yun,et al.  New compact bandpass filter using microstrip /spl lambda//4 resonators with open stub inverter , 2000 .

[13]  Chi-Yang Chang,et al.  An X-band front-end module using HTS technique for a commercial dual mode radar , 2005 .