A Low-Profile, Low-Backlobe and Wideband Complementary Antenna for Wireless Application

A new complementary antenna (or Huygens source) with a very low profile is presented. This antenna, composed of a pair of planar monopoles, a pair of bowtie shaped slots and a microstrip antenna, provides a broadband operation while its height is only, where is the wavelength referring to the center frequency of the operating band. More importantly, the proposed antenna radiates unidirectionally without the need of a metallic reflector. And therefore the total antenna volume is reduced to 0.011 lambda(3)(0). A prototype was fabricated and measured. It exhibits an impedance bandwidth (SWR <= 2) of 20.7% from 1.387 GHz to 1.696 GHz, a stable boresight gain of 6.11 dBi and a unidirectional radiation pattern with low back radiation (<-dB), low cross-polarization (<-dB).