A compact duplex slotline loop antenna with a magnetically coupled microstrip loop feeder

The paper proposes a duplex slotline loop antenna with a magnetically coupled microstrip loop feeder as a new compact dual-plane antenna. Though this antenna is small in size (the edge length of the square antenna is less than 1/8 wavelength), it realizes a reasonable radiation efficiency and a convenient omni-directional radiation pattern. The basic behavior of the antenna is studied theoretically by FDTD analysis and the results are confirmed by several experiments.