In this paper, an integrated switchable and tunable bandpass filter is designed, simulated, and fabricated. This integrated bandpass filter is able to switch as well as tune in the ultra-wideband (UWB) as well as 2.4 GHz band. At first, a UWB bandpass filter is developed which consists of two bent shorted quarter-wavelength stubs and a connecting half-wavelength stub. Subsequently, a 2.4 GHz bandpass filter is realized by connecting another half-wavelength stub on top of the UWB filter. RF pin-diodes are used for switching the bands between UWB and 2.4 GHz bandpass filter. The switchable bandpass filter converts into a tunable filter by changing the inductance or the length of shorted stubs through the pin diodes. A detailed parametric analysis is done for calculating different stubs lengths of the UWB as well 2.4 GHz bandpass filter. The simulation results show a high rejection level of >40 dB at the lower frequency and a low insertion loss of 0.8 dB in the passband for UWB filter. For 2.4 GHz bandpass filter, the simulation results show an insertion loss of 0.42 dB and a 3 dB bandwidth of 796 MHz. The filter is fabricated on a Rogers 4003 substrate, and the measurement results of the switchable filter in the UWB band show an insertion loss of 2.1 dB and a 3 dB bandwidth of 7 GHz. In the case of 2.4 GHz bandpass filter, the insertion loss is 0.78 dB.
Muhammad Faeyz Karim,
Mohammed Yakoob Siyal,
"A Compact Switchable and Tunable Bandpass Filter," Progress In Electromagnetics Research M,
Vol. 85, 71-81, 2019. doi:10.2528/PIERM19071804
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