A Compact Microwave/Millimeter-Wave Shared-Aperture Antenna With Wideband Millimeter-Wave Beam-Steering Ability

In this letter, a compact microwave (MW) /millimeter-wave (MMW) shared-aperture antenna with a wideband millimeter-wave beam-steering ability is proposed. For shared-aperture antenna, suitable substrate thickness for MW antenna is high for the MMW antenna. The design concept is to provide better performance for the MMW antenna by using a high substrate thickness. Thus, the magnetoelectric (ME) dipole antenna is used as MMW antenna due to its characteristics of high profile and wide bandwidth. The perforated patch antenna is used as the MW antenna, and the 2 × 4 MMW ME dipole beam-steering array is embedded into the MW perforated patch. Meanwhile, the MW patch improves the impedance matching of the MMW antenna. The shared-aperture antenna obtains an extreme structure of <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$0.32\lambda_{01} \times 0.27\lambda_{01} \times 0.019 \lambda_{01}$</tex-math></inline-formula> (<inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$\lambda_{01}$</tex-math></inline-formula> is the wavelength in the vacuum at 3.5 GHz). A validation model has been constructed and tested, demonstrating its capability to operate across two frequency bands: 3.4 GHz to 3.61 GHz (6.1%) and 22.6 GHz to 29.6 GHz (26.8%). The MW antenna achieves peak gains of 6.1 dBi, while the MMW array achieves peak gains of 15.2 dBi. Additionally, the MMW array enables ±40° beam scanning in H-plane.