Wideband Conical-Pattern Antenna With Stable Gain

A design of wideband antennas with conical radiation pattern is proposed. The wideband operation is achieved by coupling three resonant modes, including monopolar-patch mode, top-loaded monopole mode, and TM₀₂ mode of a ring patch, and the proposed antenna can deliver an impedance bandwidth of more than 50%. In addition, stable conical radiation with gain variation of about 1 dB within the impedance bandwidth is also realized by introducing four symmetrical parasitic elements. Each parasitic element consists of a suspended patch and two shorting pins, and its parametrical analyses are performed to obtain an optimum design. An antenna prototype is constructed, and the measured results have good agreements with simulation data.