Title :
A magnetically switchable ferrite radome for printed antennas
Author_Institution :
Dept. of Electr. & Comput. Eng., Masschusetts Univ., Amherst, MA, USA
fDate :
3/1/1993 12:00:00 AM
Abstract :
A ferrite superstrate or radom layer can be used to control the radiation, reception, and scattering from a printed antenna or array by applying a DC magnetic bias field in the plane of the ferrite, orthogonal to the RF magnetic field. By properly choosing the bias field, the effective permeability of an extraordinary plane wave propagation in the ferrite region can be made to be zero or negative over a certain frequency range, resulting in an evanescent wave behavior in the ferrite layer, and a large attenuation of the wave transmitted through the layer. Similarly, the radar cross section of the antenna will be reduced by twice this attenuation factor. A simple model capable of predicting the gross behavior of the ferrite radome layer is presented, and experimental data are shown to validate the concept.<>
Keywords :
antenna accessories; ferrite applications; microstrip antennas; microwave antenna arrays; radar cross-sections; switching; DC magnetic bias field; RCS reduction; RF magnetic field; attenuation factor; evanescent wave behavior; extraordinary plane wave propagation; ferrite superstrate; magnetically switchable ferrite radome; model; printed antennas; radar cross section; radom layer; Antenna arrays; Antennas and propagation; Attenuation; Ferrites; Magnetic fields; Magnetic switching; Permeability; Radar cross section; Radar scattering; Radio frequency;
Journal_Title :
Microwave and Guided Wave Letters, IEEE