The Design of Capacitive Coupling Bandpass Filter Using Stepped Impedance Resonator

In this chapter, the main focus is on the design of microstrip dual-band filter function. This chapter presents a new compact, low insertion loss, sharp-rejection, and capacitive coupling dual-band microstrip bandpass filter. The operation of filter was designed in dual band of WLAN 2.45 GHz and WiMax 3.5 Hz. In order to reduce the size, the proposed filter used skew symmetric feed and microstrip line ring structure. The proposed filter additional two winding-type L shape of the stepped impedance resonator increased high-frequency transmission zeros to achieve a good dual-band effect. The filter was using electromagnetic simulator Ansoft HFSS, which was used to adjust and optimize the associated parameters. The filter was fabricated by Rogers RT/duroid 6010 substrate and measured by Agilent-N5230A with the connectors. The dual-band bandpass filter experimental results are in good agreement with the full-wave simulation results. Experimental results are in good agreement with the full-wave simulation results.