Millimeter-Wave High-Gain Shorted Patch Antenna Using Hybrid TM_2,1/2 and TM_3,1/2 Modes

Using a higher-order patch radiator is an effective approach to realizing a high-gain antenna. This letter proposes a method of designing a high-gain millimeter-wave shorted patch antenna by exciting hybrid TM<sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2,1/2</sub> and TM<sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3,1/2</sub> modes. Higher-order shorted patch is half the size of the conventional patch, but its radiation pattern is split into dual beams with reduced gain in TM<sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2,1/2</sub> mode. To tackle this problem, slots are etched on the shorted patch edge to adjust the current distribution, generating additional magnetic current. As a result, the proposed shorted patch antenna has reshaped the standard broadside radiation pattern at two resonance frequencies of 24 GHz and 29 GHz, corresponding to TM<sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2,1/2</sub> and TM<sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3,1/2</sub> modes, respectively. Therefore, the antenna operating bandwidth is enhanced to be 23.3 GHz to 30.3 GHz, and the in-band gain is up to 10.6 dBi. Sawtooth-shaped stubs are used for further miniaturization. Compared with previously reported patch antennas, the proposed antenna has more compact size, higher gain, and wider bandwidth.