A Compact UHF Planar Monopole Antenna Using Magnetodielectric Ferrite Substrate

In this paper, a compact planar monopole antenna (CPMA) using magnetodielectric ferrite substrate is proposed for applications of Ultra High Frequency (UHF). The presented antenna is fabricated on the magnetodielectric ferrite substrate, relative permittivity = 15 and relative permeability = 9. The size of the antenna is largely affected by a miniaturization factor n (n = (mu'epsilon')1/2, where mu' is the real part of permeability and epsilon' is the real part of permittivity). Because of its concomitant medium to high permeability and permittivity, the multifunctional magneto-dielectric information materials become an important means to reduce the size of the antenna. Firstly, a conventional microstrip antenna is designed and manufactured with the magnetodielectric ferrite substrate. The size of this microstrip antenna is 40 x 40 x 1.6 mm(3) and its operating bandwidth is 840 MHz-930 MHz. On this basis, the proposed antenna in this paper is smaller than the conventional microstrip antenna. The proposed antenna consists of a feed line and an M-shape patch. The patch and ground plane make up the microstrip monopole antenna. The bandwidth and efficiency of the proposed antenna are enhanced by reduce the background copper plane. And the overall size of this antenna is 10 x 30 x 1 mm(3) which achieves the requirement of compact antenna. Simulations and measurements are used to study and design the CPMA using magnetodielectric ferrite substrate. The measured results in the vector network analyzer show that the -10 dB (S-11 < -10 dB) band of the antenna is 850 MHz-930 MHz (80 MHz, 8.8%). The proposed antenna is capable for wireless communications because of its simple structure and easy processing.