Low-Profile Dual-Wideband Microstrip Patch Antenna Based on Eight-Mode Resonance

This letter presents a low-profile, dual-wideband antenna designed for 5G terminals, based on eight-mode resonance. The half-mode patch antenna realizes the flexible tuning of TM<sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">0.5,0</sub>, TM<sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">0.5,1</sub>, TM<sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">0.5,2</sub> and TM<sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">0.5,3</sub> modes by etching vertical slot on the patch and introducing <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">n</i>-shaped stubs on both sides of the patch. To further extend the bandwidth, a nearly identical parasitic patch is coupled, resulting in a total of eight resonant modes. Additionally, two pairs of transverse slots are etched to enhance impedance matching. The proposed antenna has a volume of 0.447 × 0.271 × 0.011λ<sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">L</sub><sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sup> (λ<sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">L</sub> refers to the vacuum wavelength at the lowest frequency of the operation band) and an impedance matching bandwidth of 9.00% at 3.45 GHz and 7.22% at 4.85 GHz. This satisfies the requirements of China's four major communication operators, as well as certain operators in South Korea and Japan. Physical samples of the antenna were fabricated, and the measured results are presented in the letter.