Broadband and High-Gain Embedded Probe-Fed Low-Profile High-Order-Mode Antennas

In this communication, a low-profile high-order-mode (HOM) antenna fed by an embedded L-shaped probe is proposed for high gain and broadband operation. Mode distribution in this low-profile cavity is studied. Three feeding structures, including substrate-integrated waveguide (SIW), probe, and embedded probe, are discussed thoroughly regarding their effect on the HOM cavity. The quasi-metasurfaces (MTS) are introduced to suppress the performance deterioration of the proposed antenna. The mode [Formula Omitted] is excited over a wide bandwidth for improved radiation. The study shows that the proposed metasurface antenna achieves a gain of 12 dBi and a [Formula Omitted] dB bandwidth of 35.8% (4.7–6.75 GHz) with an area of [Formula Omitted], where [Formula Omitted] is the free-space wavelength at the center frequency of 5.72 GHz. In particular, the proposed HOM-fed antenna features a very low profile of 0.045[Formula Omitted].