Hawaii Center for Advanced Communications

PROJECT DESCRIPTION, MOTIVATION, & RELATED WORK
Our group has several antenna related research and design projects with the following objectives:

For the low cost multi-band antennas and antenna array, we are basically using our patented design of the coaxial continuous transverse stub (CTS) antennas. The developed designs have the advantage of low-cost, good impedance matching, multi-band, and good tolerance to manufacturing errors. Fig.1 shows prototypes of a three elements single band array operating in the X-Band, and a photograph of a fabricated six elements multi band coaxial CTS array operating at both 4.2, and 19.4 GHz. The design process is based on extensive simulation effort using a multi-grid Finite-Difference Time-Domain codes also developed by our group. Through some new research funding received from the Army Research Office, we plan on developing new versions of these deigns including the use of photonic band gap (PBG) magnetic planes to reduce the antenna size in half while maintaining its omni-directional characteristics in half space, and also to use Ferroelectric material to provide beam steering capability. These two projects are extremely challenging as the design of the PBG continues to be empirical and both simulation and experimentation intensive, and the use of Ferroelectric materials is still in need of an innovative approach to overcome the significant reduction in the impedance of the loaded devices and hence avoid the unacceptably large values of Ohmic losses.

Fig. 1. Photograph of the prototype X-band three-element Coaxial CTS array.

Fig. 2. Photograph of fabricated multiband six-element coaxial CTS antenna array designed to operate at 4.2 and 19.4 GHz