Compact Transverse-Resonance Low-Pass Filter With Wide Stop-Band Rejection Implemented in Gallium Arsenide Technology

This work reports three designs of transverse resonance (TR)-based high-performance compact 5-pole Butterworth low-pass filters (TR-LPFs) at the cut-off frequency ( $f_{c}$ ) 10.5 GHz in $0.15~\mu \text{m}$ Gallium Arsenide (GaAs) pHEMT technology, with a chip size of 0.82 mm $\times0.87$ mm. Two fabricated TR-LPFs have 20 dB, 30 dB, 40 dB, and 50 dB attenuation levels with rejection bandwidths of (54 GHz, 54 GHz), (32 GHz, 52 GHz), (31 GHz, 50 GHz), and (18.5 GHz, 27 GHz) respectively, and insertion loss of 0.5 dB and 0.6 dB. The TR-LPF is a microstrip-based design, so unlike the lumped elements-based design, it could be designed and fabricated in the GaAs, and other technologies even at millimeter-wave frequencies. Such high performance LPF, using microstrip on a GaAs chip is not reported in the open literature.