A Simple Way to Enhance the Isolation of Ridge Gap Waveguide T-Junction, for Application to Millimeter-Wave Feeder Networks

In this letter, a simple technique for enhancing the isolation of a ridge-gap waveguide (RGW) T-junction power divider is proposed. In detail, we have succeeded in improving the isolation characteristics of a normal T-junction by a factor of ~10 (>15-dB), while the operation is simply the introduction of an appropriately sized radiation slot in its lid. Compactness is, therefore, the primary advantage of this solution, as there is no need to use any load terminations. Such a quasiplanar configuration means that it can be applied to large-scale feeder networks like an original T-junction (regardless of vertical or horizontal space constraints when ranking the array). A four-way feeder prototype operating in the
${W}$
-band was fabricated to validate the scheme, and the measured results showed good agreement with the simulated predictions, both demonstrating excellent RF performance.