Office of Technology Transfer – University of Michigan

Miniaturized Radio Repeater

Technology #4449

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Kamal Sarabandi
Managed By
Joohee Kim
Licensing Specialist, Physical Sciences & Engineering 734-764-8202
Patent Protection
US Patent Pending


In a wireless network, the path loss between the transmitter and receiver is a critical factor that determines the possible range of communication between the two nodes. Complex environments such as urban canyons and building interiors often contain numerous obstacles that impede the line-of-sight communication and increase the path loss. In these environments, and especially at high frequencies, the path loss dramatically increases, which often requires higher transmitter power and/or closely spaced communication nodes, potentially adding complicating interference issues. To overcome these situations and to help improve the ground area coverage of communication signals without increasing the transmitter power, radio repeaters have been used extensively in various scenarios and numerous studies have demonstrated their feasibility and operation.


Researchers at the University of Michigan have developed a new device that overcomes the adverse effect of complex environment by reducing the path-loss. They have invented a very small radio repeater with large radar cross-section and omni-directional pattern to enhance radio connectivity and maintain low-power communication. This repeater consists of two miniaturized planar antennas, separated by a metamaterial band-gap structure, and compact amplifier with low power consumption. The antennas and the band-gap occupy a very small and short area, which is capable of supporting vertical polarization.

Applications and Advantages


  • Wireless networking with radio connectivity


  • Reduces path loss
  • Small size
  • Low fabrication costs