UWB microwave image radars [3]. The ringing will be reduced using resistive loads. CONCLUSIONA UWB planar stepped-fat dipole antenna has been proposed for the applications to high-resolution UWB microwave image radars using impulse waveforms. Design procedures and numerical results are presented. A prototype of the stepped-fat dipole antenna was fabricated and measured. Measurement and simulation shows that the antenna has much wider bandwidth than a conventional fat dipole antenna. Also, using the stepped-fat arms, a simple feeding technique like a SMA connector is possible. From the impulse response of the antenna, the antenna has ringing and dispersion that should be removed for the better performance of UWB image radars, whereas the antenna has good radiation patterns and lowreflection coefficient for ultra wide bandwidth in frequency domain. It is expected that the developed antenna can be applied to multiband communication systems due to low cost, easy fabrication, and UWB behavior. 2. Joint special session on, Through wall microwave sensing and imaging, IEEE AP-S International Symposium and USNC/URSI National

The S-parameters of a gold wire bonded in air to two microstrip lines are validated by measurements and HFSS software simulations at frequencies 0.04~6 GHz. From simulation results and measurement data, it is found that an arching bond wire with smaller arc angle can minimize the return loss. From simulations, it is also found that the return loss can be improved and operation frequency shifts can be achieved by using multiple wires placed in parallel in bond wire arrays.