A MINIATURIZED QUAD-BAND BANDSTOP FILTER WITH HIGH SELECTIVITY BASED ON SHUNT-CONNECTED, T-SHAPED STUB-LOADED, STEPPED-IMPEDANCE RESONATORS

作者：Adhikari Kishor Kumar^*; Kim Nam Young

来源：Microwave and Optical Technology Letters, 2015, 57(5): 1129-1132.

DOI：10.1002/mop.29046

• miniaturized size
• selectivity
• trisection stepped-impedance resonators
• T-shaped stub load
• quad-band bandstop filter

This letter presents a microstrip quad-band bandstop filter (QBBSF) with a miniaturized size and high selectivity. The structure of the proposed QBBSF consists of two-folded, shunt-connected trisection stepped-impedance resonators (TSSIRs). One of these TSSIRs, which operates on the second and fourth central frequencies, has been embedded inside another TSSIR operating at the first and third central frequencies of the proposed QBBSF. Characterized by equivalent circuit analysis and full-wave EM simulations, each TSSIR has been miniaturized by a T-shaped stub load. The main advantage of the proposed QBBSF lies in its central frequencies, which can be adjusted conveniently within a wide range by varying parameters of TSSIRs, the positions, and dimensions of the stub loads. A protocol QBBSF with a compact size of 0.0115 lambda(2)(g) operating at central frequencies of 1.90, 3.32, 5.77, and 6.75 GHz was designed, simulated, and fabricated to verify the proposed method. The measured minimum stop band return loss of 21.4 dB and maximum pass band insertion loss of 0.66 dB indicated the excellent in-band and out of band selectivity of the proposed QBBSF.

• 出版日期2015-5