A wideband circular patch antenna with broadside and conical radiation patterns is proposed. In addition to realizing a wide shared impedance bandwidth of ~48% for both the modes of operation, the unparalleled advantage of the proposed antenna is its reduced sidelobes in the E-plane broadside radiation patterns. The achieved sidelobe-free bandwidth is in the order of 39%, which is much wider than the pertinent art works on wideband pattern diversity antennas using a single radiating patch. The antenna characteristics are validated by fabricating and testing the designed prototype. The proposed antenna is also numerically investigated in front of a parabolic reflector antenna for monopulse radar applications.