Radiation characteristics of a switchable microstrip planar array of circul
ar patch antennas printed on ferrite substrate with a normal magnetic bias
field are described. The extra degree-of-freedom offered by the biased ferr
ite can be used to obtain a number of novel characteristics including switc
hable and tunable radiations from a microstrip antenna with a single feed p
oint. In such a case for antenna radiation, most of the power will be conve
rted into magnetostatic waves and little radiates into the air. Under such
circumstances the antennas are off, in the sense that they are effectively
absent as radiators. Properties of a switchable antenna in an S band (3GHz)
are investigated.