Low-Profile, Cavity-Backed Slot Antenna Using a High Impedance Reflector

Tech ID: 10194 / UC Case 2000-375-0


Antennas used in airborne and satellite communications need to be flush mounting, low cost and lightweight. Cavity-backed slot (CBS) antennas meet these criteria. The cavity height is usually designed such that it is one or three-quarter wavelengths of the resonator frequency, which maintains good impedance matching. The cavity volume can be reduced through dielectric loading, but at the cost of reducing bandwidth and efficiency.


Scientists at the University of California have developed a low-profile CBS antenna with a very thin cavity. The design uses a grounded dielectric substrate as both a reflector in the cavity as well as an open circuit boundary at the resonant frequency to maintain good impedance matching.


This invention has applications in several areas, such as:

  • Airborne communication;
  • Phase-array antennas;
  • Satellite communications;
  • Wireless local area network;
  • Microwave energy transmission systems.


The new UC technology provides the following benefits:

  • Very low-profile design (thickness is only lo/28, rather than lo/4 for conventional CBS antennas);
  • Easy to fabricate, due to its planar feature;
  • Can be readily applied to cavity-backed slot arrays.

Patent Status

Country Type Number Dated Case
United States Of America Issued Patent 6,518,930 02/11/2003 2000-375


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