Title :
Radiation Characteristics of a Microstrip Patch Over an Electromagnetic Bandgap Surface
Author :
Liang, Jing ; Yang, Hung-Yu David
Author_Institution :
Illinois Univ., Chicago
fDate :
6/1/2007 12:00:00 AM
Abstract :
Radiation characteristics of a microstrip patch over an electromagnetic bandgap (EBG) substrate are investigated in this paper. This paper focuses on a mushroom-type EBG structure, although the design is applicable to various EBG profiles. The patch antenna is modeled as a half-wavelength resonator of an EBG-loaded microstrip transmission line. Through a full-wave eigenmode analysis of a microstrip line on an EBG structure, it is found that the resonant patch will not see a high-impedance surface (HIS), but rather it is coupled to the EBG structure as an open cavity resonator. Due to strong near-field coupling, the propagation characteristics including the bandgap zones are very different with or without the patch cover. The use of an EBG structure as a bulk material for antennas is seen inappropriate. The EBG surface is found to have the effect of reducing the patch resonant length and bandwidth. A prototype of a microstrip line proximity fed to a patch antenna is fabricated and tested to verify the analysis.
Keywords :
antenna radiation patterns; cavity resonators; electromagnetic wave propagation; microstrip antennas; microstrip lines; photonic band gap; cavity resonator; electromagnetic bandgap surface; full-wave eigenmode analysis; half-wavelength resonator; microstrip line proximity; microstrip patch antenna; microstrip transmission line; mushroom-type EBG structure; radiation characteristics; Cavity resonators; Couplings; Electromagnetic radiation; Metamaterials; Microstrip antennas; Microstrip resonators; Patch antennas; Periodic structures; Photonic band gap; Resonance; Electromagnetic bandgap (EBG); high-impedance surface (HIS); microstrip patch antenna; periodic microstrip line;
Journal_Title :
Antennas and Propagation, IEEE Transactions on
DOI :
10.1109/TAP.2007.898633