Millimeter-Wave Ultrawideband Antenna With Hybrid-Mode Resonance Including Microstrip Line, Slot, Patches, and Quasi-Monopole Modes

A novel millimeter-wave (mmWave) ultrawideband (UWB) antenna covered from 24.25 to 50 GHz is proposed in this letter. Different from previous broadband antennas that use a single resonant mode or radiating structure, the proposed antenna demonstrates a hybrid-mode resonance including microstrip line, slot, patches, and quasi-monopole modes with stable radiation patterns. The antenna is fed by a microstrip line with an open terminal, and the energy is coupled through the slot to the top patches, quasi-monopoles, and short strips. The overall thickness of the antenna element is only about 1 mm. An antenna element is designed, fabricated, and measured as verification. Measured results show that the proposed antenna can realize a −10 dB impedance fractional bandwidth (FBW) of more than 69.4%. The 3 dB gain bandwidth of the antenna element covers from 24.25 to 47.9 GHz with a peak gain of 6.97 dBi. With the UWB, low profile, and stable radiation characteristics, the proposed antenna can be a good candidate for many mmWave applications, such as N258 (24.25–27.5 GHz), N257 (26.5–29.5 GHz), N260 (37–40 GHz), N259 (39.5–43.5 GHz), and IEEE802.11aj (42.3–48.4 GHz).