Quasi-Isotropic Radiation by Coupled Loop Antennas Without a Quadrature Phase Shifter

We present a quasi-isotropic antenna by combining two electrically small and nearly perpendicular loops with a quadrature(90°) phase difference. Instead of feeding both loops with a quadrature phase shifter, only one loop is fed and the other loop current is induced by coupling from their deviated angle from 90°. 10 × 10 × 10 mm sized, two loops at an angle of 85° are simulated at 433 MHz and shown 4.2 dB of the radiation gain difference in all three dimensional directions.