| Leaky-wave antennas have been an on-going research interest of U.S. government, academic and industrial research groups. One significant feature of these antennas is that the voltage standing wave ratio (VSWR) bandwidth can be greater than that of resonant antennas. This is principally due to the fact that the radiation mechanism is attributed to a traveling-wave as compared to the standing-wave that is responsible for radiation in resonant antennas. Another important aspect of leaky-wave antennas is that the radiation pattern bandwidth is regrettably somewhat narrow since the main-lobe direction varies with operational frequency. This dissertation deals with the effective design of trough leaky-wave (TLW) antennas A TLW antenna is an electrically narrow trough in a ground plane excited using a coaxial probe feed and terminated in a lumped load. In this antenna, a traveling wave propagates along the aperture with a complex propagation constant which can be computed using the transverse resonance method (TRM) assuming an infinitely long antenna. An alternative approach, that considers the aperture length, is the finite element boundary integral (FE-BI) method. In this work, both formulations are developed and implemented numerically not only to compute the propagation constants but also the antenna impedance and radiation pattern. The major contribution of this work lies in the balun used to feed in concert with the load to terminate the antenna. |
