Defense Event

Antenna Bandwidth and Radiation Control by Topology and Use of Non-Conductivity Materials

Hatim Bukhari

PhD Candidate
Monday, November 23, 2015
3:00pm - 5:00pm
3316 EECS

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About the Event

Ultra-wide-band (UWB) antennas have become one of the hottest topics in the last decade in wireless communications and radars. There are many different applications such as ground penetrating radars (GPRs) and wireless communication systems where such antennas are highly recommended and desired. The size of the antenna is also a major factor and design considerations must take into account the antenna size as well as is radiation characteristics into account. Many topologies and configurations have been studied and reported in designing UWB antennas. These topologies are corresponding to radiation pattern, polarization, and band of operation. In addition, in low frequencies, such as in VHF and UHF bands, the size of the antenna becomes a major factor that must be taken into consideration. A new approach in design of a cavity-backed coupled sectorial loop antenna (CB-CSLA) with directional radiation pattern is presented. This antenna is backed by a short cylindrical cavity with a special modal suppressing septum to accomplish unidirectional radiation pattern while maintaining a very wide bandwidth. A prototype is fabricated to validate the design and it is shown that a CB-CSLA with diameters of λ/4 and height of λ/5 can provide a fabricated bandwidth of 38% and front to back ratio of 15dB. For communication applications, a novel miniaturized impedance matched antenna with omnidirectional horizontally polarized radiation pattern is then presented. The antenna structure resembles a circular loop formed by a circular array of shunt miniaturized n-fold resonant dipole antennas which is referred to as miniature composite wire-loop antenna (MCWLA). This antenna has a diameter of λ/9 and a height of less than λ/500. The measured gain and radiation efficiency are, respectively, 0dBi and 67%.

Additional Information

Sponsor(s): ECE

Faculty Sponsor: Kamal Sarabandi

Open to: Public