A Self-Packaged SICL-based Integrated Antenna-Diplexer System Featuring High Isolation and selectivity

This article proposes a new design procedure for the development of a highly selective diplexer and its integration with a high-gain antenna. The proposed diplexer conceived by two SICL-based bandpass filters and an impedance matching network exhibits low insertion loss and excellent out-of-band rejection. The proposed SICL-based diplexer exhibits high selectivity, and multiple transmission zeros which aid in achieving steep rejection skirt as well as excellent out-of-band rejection. The self-shielded structure and multiple transmission zeros outside the band of operation provides a high measured isolation greater than 48 dB at both transmit and receive bands of the proposed diplexer, while maintaining a low profile and planar form factor. Additionally, a design for a SICL-based T-junction power divider with suitable electrical lengths and characteristic impedance selection is presented for two output sections operating at different frequency bands. A wideband high gain linearly tapered antipodal antenna is realized for a frequency range of 11 to 18 GHz. The SICL diplexer-antenna integrated system has a peak gain of 13.8 dBi at 11.21 GHz and 13.15 dBi at 13.85 GHz.