Radiation Performance of Switchable Ferrite Microstrip Array Antenna

This letter reports radiation performance of switchable microstrip planar array of 6 $,times,$6 element circular patch antenna printed on Ni¿Al ferrite substrate with a normal magnetic bias field. The extra degree of freedom offered by the biased ferrite can be used to obtain a number of novel characteristics including switchable and tunable radiation from a microstrip antenna with a single feed point. Under certain bias conditions, most of the power is converted into magnetostatic waves and little radiates into air. Under such circumstances, the antennas are highly inefficient, in the sense that they are effectively absent as radiators. The bias dependent properties of a switchable antenna in S band (3.5 GHz) are investigated.