LAUSR

In this paper, we propose a novel Half Mode Substrate Integrated Coaxial Line (HMSICL) cavity fed monopole antenna at 28 GHz. A SICL cavity is bisected along its symmetric magnetic wall (PMC) to create an open-ended Half Mode SICL (HMSICL) cavity. The proposed HMSICL cavity is used to excite a tapered monopole antenna to radiate in endfire direction with a gain of 6.4 dBi at 28 GHz. For dual beam application, it is integrated with unidirectional broadside Half Mode Substrate Integrated Waveguide (HMSIW) antenna exhibiting a gain of 5.1 dBi that provides spatial diversity to the proposed design. To achieve high gain, two co- located $1\times 4$ linear HMSICL and HMSIW array are placed side-by-side such that the proposed design produces simultaneous endfire and broadside beams for In-Band Full Duplex (IBFD) applications. The proposed passive Signal Interference Cancellation (SIC) technique is utilized to minimize the overlap of simultaneous dual beam at 28 GHz by orienting the two antennas within a compact footprint. The full duplex antenna array achieves a gain of 10.8 dBi in endfire and 10.3 dBi in broadside direction with high isolation below 45 dB over 500 MHz bandwidth. The presented antenna array is a potential candidate for relay where the transmitting and receiving signals are in two different directions.