Design of Broadband and High Gain Miniaturized HMSIW Antenna with Band Rejection Filter

This paper proposes a design for miniaturized HMSIW antenna bandwidth and improved matching, which can be applied to smart wearable devices in the 5G NR mmWave frequency band. By etching an open slot on the body of the half-mode substrate integrated waveguide antenna, the structure can be equivalent to a broadband rejection filter resonant structure composed of two band rejection filters, which can greatly suppress the low-frequency periodicity in front of the main communication frequency band resonance. The slow wave effect and the frequency offset effect are provided in the structure by using the delay characteristic of the coupled and connected paths, which helps to improve the matching characteristic in the frequency band. The band-rejection filter slope is used to slow down the impedance variation trend, thereby obtaining the required bandwidth. The size is 64.94x9.32x0.45 mm(3), the bandwidth is increased by 2.41GHz compared with the prototype structure to meet the frequency band of n257, covering 26.24 similar to 29.75GHz, the gain of the whole frequency band can reach more than 10dBi with the gain changes slowly, the half power beamwidth is 10.5 degrees similar to 17.5 degrees. The proposed antennas are studied in both simulation and experiments.