Broadband dual varactor diode-loaded elliptical slot antenna with an orthogonal feed at K-band

An orthogonally-fed, small elliptical slot antenna loaded by a varactor diode, and operating in K-band frequency range (18 - 26.5 GHz), is designed for use in synthetic aperture radar imaging arrays. The broadest dimensions of the antenna are restricted to being less than λ/2 as a consequence of required spacing in an imaging array. The feed design uses a coplanar waveguide with a 90° bend without a direct DC connection to the antenna. The final slot employs two varactor diodes resulting in 3.5 GHz of bandwidth suitable for microwave 3D holography imaging.