Performance analysis of atomic magnetometer and bandwidth‐extended loop antenna in resonant phase‐modulated magnetic field communication system

Abstract

AbstractTelecommunications through an electrically conductive medium require the use of carrier bands with very‐low and ultralow frequencies to establish radiofrequency links in harsh environments. Recent advances in atomic magnetometers operating at very‐low frequencies have facilitated the reception of digitally modulated signals. We demonstrate the transmission and reception of quadrature phase‐shift keying (QPSK) signals using a multi‐resonant loop antenna and atomic magnetometer, respectively. We report the measured error vector magnitude according to the symbol rate for QPSK modulation and analyze the bandwidth of a receiver based on the atomic magnetometer. The multi‐resonant loop antenna noticeably enhances the bandwidth by over 70% compared with a single‐loop antenna. QPSK modulation for a carrier frequency of 20 kHz and symbol rate of 150 symbols per second verifies the feasibility of demodulation, and the measured error vector magnitude and signal‐to‐noise ratio are 7.29% and 30.9 dB, respectively.