A parametric-excitation-integrated-ferrite antenna

A new type of ferrite antenna with fairly high sensitivity has been studied and experimental results are presented. Although ferrite antennas have long been used as one of the typical antennas of small size, it seems that the remarkable increase of the sensitivity of the ferrite antennas depends upon dimensions and performance of ferrite material, and improvement of those factors is not expected so easily at the present state of the art. One solution for this problem may be the application of the integration technique, that is combining an antenna and active devices in a unified structure with an inseparable form. To form an active device within an antenna, parametric excitation is incorporated into a ferrite antenna structure, and the principle of power transfer between signals, which follows Manley-Rowe´s relation, is applied to it for obtaining an active gain within the antenna itself. The permeability variation of the ferrite material is effectively utilized to produce an active function from a passive antenna system. Results show about 5 to 10 dB gain depending upon the pumping power interims of S/N over the conventional passive ferrite antenna having the same size as that of the active antenna.