A Compact and Easy to Fabricate $E$ -Plane Waveguide Bend

Abstract

In this letter, we present a new $E$ -plane rectangular waveguide bend that can be micromachined using split-block fabrication. The 90° bend is created by machining two linear channels with a notch left in the outside corner. This notch significantly improves the return loss and the insertion loss of the bend. The primary advantage of this technique is that it produces a compact waveguide bend, minimizing both the size and the conduction loss of the waveguide circuit. Another advantage is that this technique only requires linear channels to be machined, thus it can be fabricated without requiring a computer numerically controlled (CNC) milling machine. The performance of this waveguide bend was optimized using electromagnetic simulation software, and the optimal reflection coefficient was found to be below −28 dB across the entire operational bandwidth of the waveguide. The simulated design was then validated using two experimental prototypes that were tested at microwave (12–18 GHz) and millimeter frequencies (140–220 GHz).