Wideband SIW Self-Diplexing antenna with simultaneous control of bandwidth and band position

This paper presents a wideband self-diplexing antenna in substrate integrated waveguide (SIW) technology. The problem of narrow radiating bands of traditional self-diplexing antennas is first solved by introducing stepped-impedance resonant slots on top of an SIW cavity. Radiation in each band is obtained from two modes of the resonator, which helps in bandwidth improvement. Bandwidths are controllable by the stepped impedance parameters. Good isolation between the ports enables almost independent control of the band position. Further, a third non-radiating slot is introduced in the middle of the structure, which improves input matching at both the ports. A prototype antenna is fabricated for X-band wireless systems. The measured 10 dB bandwidths are 12.65% (9.25-10.5 GHz) and 17.24% (10.6-12.6 GHz) with the boresight gain ranging over 7-9 dBi and 8.4-10.6 dBi, respectively. Even though the band separation is just 100 MHz, measured isolation is at least 20.5 dB. Isolation can be further improved for wider band separation. The present antenna can be directly integrated with microwave circuits because it does not use any ground plane perturbation.

Automated summary

This paper presents a wideband self-diplexing antenna in SIW technology, solving the narrow radiating bands problem of traditional self-diplexing antennas by introducing stepped-impedance resonant slots. Bandwidths can be controlled by the stepped impedance parameters and good isolation between ports allows almost independent control of band positions. The introduction of a non-radiating slot in the middle improves input matching at both ports.