Sharif University of Technology

University of Michigan

Behzad Yektakhah

Fatemeh Akbar

Kamal Sarabandi

Abdulrahman Aljurbua

An antenna comprises a substantially circular ground plane with an upper surface and a defined center. A plurality of radiating elements are placed radially on the upper surface, arranged at constant angles around the defined center to, when electrically excited, create a plurality of circularly polarized electromagnetic emissions. Each radiating element of the plurality of radiating elements is in electrical communication with an electromagnetic source via an electrically conductive feed, the electromagnetic source configured, when in use, to create a radial excitation current on the radiating element, and further configured, when in use, to provide phase and amplitude control of the excited current on the radiating element for both beam forming and 360 degree beam steering by superposing omnidirectional circularly polarized electromagnetic emissions.

Systems and methods for circular-polarized beam forming and steering based on the superposition of circular modes for communication and radar systems

A subsurface imaging technique using distributed sensors is introduced. Instead of monostatic transceivers employed in conventional ground penetrating radars, the proposed technique utilizes bi-static transceivers to sample the reflected signals from the ground at different positions and create a large two-dimensional aperture for high resolution subsurface imaging. The coherent processing of the samples in the proposed imaging method eliminates the need for large antenna arrays for obtaining high lateral resolution images. In addition, it eliminates the need for sampling on a grid which is a time-consuming task in imaging using ground penetration radar. Imaging results show that the method can provide high-resolution images of the buried targets using only samples of the reflected signals on a circle with the center at the transmitter location.

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Ann Arbor, MI, United States of America

Behzad Yektakhah