Bandstop filter (BSF) is first constructed using open stubs and spurline. The stop bandwidth of this conventional structure is further increased by placing a complementary split ring resonator (CSRR) exactly below the 50 Ω microstrip line. By embedding this BSF with a wide rejection band in the input port of the PCML bandpass filter, unwanted passbands of bandpass filter is eliminated. To demonstrate this, we have designed, fabricated and tested a first order Chebyshev bandpass filter centered at 0.9 GHz with 10% fractional bandwidth (FBW). This bandpass filter is cascaded with the newly proposed BSF. Simulation and measured results shows a harmonic rejection upto 5f0 with more than 20 dB rejection level.
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