A novel wideband waveguide antenna with excellent performance tourettebrewing.com is proposed, which is composed of a coaxial-waveguide transition and an open-ended rectangular waveguide loaded with a pair of horizontal umbrella-shaped metallic brims.The brims perpendicular to two broad walls of the waveguide are constructed to modulate the antenna to radiate nearly identical E- and H-plane radiation patterns.A wideband impedance matching performance is achieved with a fractional bandwidth of 40% through the introduction of short-stepped ladders.The antenna has the pentair hose advantages of simple structure, symmetric radiation pattern, low-cross polarization, moderate back lobe, and almost constant beamwidth.