Leaky-Wave-Enabled Horn Antenna Exhibiting Customizable Contour and Wideband Radiation Characteristics for Millimeter-Wave Applications

Conventional horns inevitably suffer from the phase error issue and associated design constraint of contour (e.g., the optimum criteria are typically employed) because of the embedded plane-to-cylindrical (or spherical) wavefront conversion process. These design dilemmas can be well addressed by using the leaky-wave enabled horn (i.e., the leaky horn), which mainly exploits the intrinsic plane-wavefront characteristics of leaky waveguides’ wedge-shaped regions. While noticing that previously reported leaky horns are subject to a narrowband nature and somewhat limited contour designability, a leaky horn class exhibiting wideband and customizable contour characteristics, which are based on a leaky grounded coplanar waveguide (GCPW), are developed in this communication. After establishing the theoretical relationship between the aperture length, flaring angle, and leakage constant of a general leaky horn and revealing several relevant design considerations, design technicalities and procedures for simultaneously realizing customizable contour and wideband radiation are systematically described for the GCPW leaky horn. For demonstration, a GCPW leaky horn example using the slow-wave technique is constructed, simulated, and measured. It is verified that the proposed GCPW leaky horn has several merits like customizable contour, wide bandwidth, suppressed phase error, compact size, etc., which enable it to be a potential candidate for millimeter-wave applications.