Two‐plane waveguide coupler with arbitrary coupling ratios in the H‐plane and E‐plane directions

Abstract

AbstractA comprehensive theoretical analysis of two‐plane waveguide coupler with arbitrary coupling ratios in the H‐plane and E‐plane directions is provided and a design of the two‐plane coupler with coupling ratio in the H‐plane direction and coupling ratio in the E‐plane direction is reported. The analysis of the two‐plane waveguide coupler is fully refined and accomplished by the authors. To realise an arbitrary and different coupling ratio in the two directions, it is crucial to specifically constrain the transition phase of the quarter model of the two‐plane coupler for different boundaries as necessitated by mode polarity. A prototype of the proposed two‐plane coupler is manufactured and measured to verify the concept. Its performance is observed from 27.0 to 29.5 GHz (8.85% fractional bandwidth). The measurement results are basically in accord with the simulation results, demonstrating the reliability of the theoretical analysis. Finally, samples of designed conventional H‐plane and E‐plane couplers are provided, cascading of which can realise the same functionality as the proposed two‐plane coupler. Compared with one‐plane couplers, the two‐plane coupler reported realises overall miniaturisation rates in terms of length and volume around 58.4% and 50.1%, respectively. According to the demonstration and verification of the two‐plane couplers having arbitrary coupling ratios, the employment of the two‐plane couplers to replace the conventional one‐plane couplers to realise miniaturisation of 2‐D beam switching matrices will be promoted in future applications.