Technology Transfer SSC Pacific
Passive Wide-band Low-elevation Nulling Antenna

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A small, wideband antenna that transmits and receives satellite and GPS communications with immunity to interference or jamming at the horizon

The U.S. Navy seeks to commercialize U.S. Patent 7,889,151 (Passive wide-band low-elevation nulling antenna).


Satellite and GPS signals are relatively weak and thus vulnerable to deliberate and unintentional interference. Electronically-steered antenna array systems, such as  Controlled Reception Pattern Antennas (CRPAs), effectively mitigate interference by steering beams and positioning nulls. CRPAs are limited in that they generally null only a small number of sources, do not null sources at the horizon (such as jamming signals from hostile ground forces), require power, and are large and heavy. Additionally, CRPAs are costly and complex. There is a need for a simple, low cost antenna that overcomes these limitations while sharing the benefits CRPAs offer.

The Technology

Inventors at SSC Pacific have created a small, lightweight, wideband, wide beam pattern, passive antenna that is able to transmit and receive signals to and from satellites at any position relative to the antenna, and is immune to interference and jamming at the horizon. The antenna consists of a spiral arm radiating element connected to a feed conductor and housed in a support structure. When the antenna is placed on a planar surface, the distance from the surface to the element (height) is about one-fourth the wavelength of the antenna’s operating frequency, effectively providing a frequency range ratio of about 3:1. The structure can be made to have an adjustable height, increasing the frequency range ratio to about 10:1. The antenna produces an onmi-directional antenna pattern in azimuth and a broad antenna pattern in elevation, with nulls near the horizon . This enables the mitigation of numerous interference/jamming sources at the horizon. For the commercial sector, the antenna could be used to mitigate interference in high radio frequency areas, such as the presence of L Band satellite communication frequencies near radio stations.

Key Benefits

  • Nulls jamming and interference near the horizon at any elevation level
  • Radiates to cover the entire sky (does not have to be pointed at/track with satellites)
  • Operates passively
  • Operates over a 3:1 bandwidth; can be adjusted to handle a 10:1 bandwidth
  • Facilitates both right-hand and left-hand circular polarization (reversible element)
  • Is small (7.5 inch diameter), lightweight (2.5 pounds), inexpensive and easy to manufacture (does not have circuitry or mechanical parts)
  • Development Status

  • U.S. Patent(s) issued: 7,889,151
  • Total R&D: $50K and 1 year
  • DoD 5000 Series Technology Readiness Level 6: System/subsystem model or prototype demonstration in a relevant environment
  • For more information on technology transfer, please contact us at (619) 5535118 or email       
    SD 991, April 2012. SSC Pacific, San Diego, CA 921525001. Approved for public release; distribution is unlimited.

    SSC Pacific
    Updated: 4/17/2012 2:16 PM EST   Published