A broadband antenna design using aperture filter circuit for smartphone operating in GPS L5/N77/Wi-Fi 5G tri-band

Abstract

Design of multiband antennas supporting GPS L5, N77, and Wi-Fi 5G remains challenging. This paper proposes an aperture tuning method for multiband antennas that applies a filter circuit at the quarter wavelength of N77 radiator to achieve independent tuning for each band, and has the characteristics of simplicity, low cost, and miniaturization. This filter circuit exhibits different impedance characteristics in GPS L5/N77/Wi-Fi 5G. Furthermore, a band-pass filter is added between Wi-Fi 2.4G and Band 40 to decouple. Results based on a real smartphone show this design meet requirements of -6 dB impedance bandwidth, with isolation of 18.3 dB. The obvious advantages in terms of frequency band coverage, efficiency improvement, and isolation optimization make it highly compatible for modern smartphone applications that require high performance and compact integration.