Design and Numerical Analysis of a Ka-Band Patch Antenna for Structural Health Monitoring Applications

This paper presents a design of Ka-Band microstrip patch antenna array for structural health monitoring (SHM) applications. Following a successful SHM system for wind turbine blades, the antenna is developed for the frequency band 33.4 GHz - 36 GHz. Horn antennas in the current system could be replaced with microstrip patch array for better integration, possible radome utility, smaller dimensions with similar antenna gain, and lower signal loss due to interconnects. The array is constructed from 4x4 radiating elements, probe fed with capacitive coupling. This approach assures dual-polarization capabilities in the future in contrast to standard aperture approaches. A novelty is also the introduction of integrated cavities, which improve antenna bandwidth and patterns. Simulation results show relative impedance bandwidth (return loss better than 15 dB) of 13.1 %, at resonance frequency f
_o
= 35 GHz. Gain is about 17.3 dBi, and side-lobe level (SLL) is lower than -15 dB on E-plane (φ = 0°).