Compact-Size Bandpass Filter for S-Band Transceivers of LEO Satellites

This paper introduces a variety of designs for low-cost and compact-size bandpass filter (BPF) proposed for S-band space-links between ground stations and low earth orbit (LEO) satellites. The proposed designs implement multiple cascaded coplanar waveguide (CPW) resonators with either single or double resonance. The first design is a compact dual-band BPF of dimensions 13 x 11 mm(2) that can operate simultaneously for both the uplink and downlink in an S-band transceiver. The second design is a single-band BPF of dimensions 25 x 10 mm(2) that can operate for the space uplink. The third design is a compact single-band BPF of dimensions 17 x 12 mm(2) that can operate for the space downlink The three designs are compact size, low cost, and high performance BPFs. The dual-band BPF design is based on dual-resonance mechanism where the resonant structure is constructed as two overlapped quarter-wavelength and half-wavelength CPW resonators; each of them operates in its first-order resonance. The single-band design is based on a quarter-wavelength CPW resonator. Three prototypes are fabricated for the proposed filter designs and their frequency responses are assessed through simulation and experimental measurements showing good agreement. It is shown that the implemented designs satisfy the operational requirements for the assigned space link with high performance, good impedance matching, and low insertion loss.