Micromachined SU-8-Based Terahertz 8×8 Slotted Waveguide Antenna Array

This article presents the design and fabrication of a micromachined 300 GHz planar array slotted waveguide antenna utilising the silver-coated SU-8 photoresist layer technology. The array is configured to be built from five SU-8 layers of equal thicknesses. The top layer is devoted to form the 8×8 slots. The following three layers are to form the feed and radiating waveguides. The bottom layer is to enclose the design and allocate the input port. An H-plane waveguide bend based on the matching steps is designed and integrated with the proposed array. This is to maintain a precise alignment with the standard waveguide flange WR-03 and facilitate the measurement. Also, two brass plates are used to clamp the five layers together and tight them via screws in order to minimise the losses. The simulated antenna realised gain is 24.59 dBi, and the 3-dB gain bandwidth is 4.5 GHz. The radiation patterns are very directive, having low side lobe levels. The reflection coefficient has been measured and presented. The proposed micromachined antenna array is directional and low-profile and may find applications in indoor wireless applications and sensors.