Design and development of Interdigital Band pass filter for L-Band Wireless Communication Applications

Abstract

New age wireless applications demand sharp rejection of unwanted signals at MHz frequencies. This necessitates the design of low loss, high attenuation bandpass filters. This paper proposes a design of compact 0.5 dB Chebyshev interdigital bandpass filter (IDBPF) which operates at a frequency of F0=875MHz used for space applications. The IDBPF is designed for an order n=9. Advanced Design System (ADS) software is used to design the filter. The designed filter is fabricated on a RO4350B substrate which has a relative dielectric constant $\varepsilon_{r}$ of 3.66. Filter has pass bandwidth of $F0 \pm 125MHz$, and insertion loss of $5 \pm 3dB$ at 875MHz with steep rejection of 40dB min at 1050MHz and 25dB min at 650MHz. In this design, rejection is considered at prime importance than the insertion loss.