An efficient 95-Ghz, rf-coupled antenna

This paper presents an efficient, RF-coupled, 95-GHz undulatory (snake-like) antenna that can be fabricated using IC technology. While there are many uses for directed power at this frequency our interest is in understanding the propagation of the input power through the circuit and its radiative characteristics for comparison to earlier work in the THz range (see PAC05). 95 GHz was chosen because test equipment was available (WR-10 waveguide and HP network analyzer). Different materials, heights and widths of the circuit were considered on a low-loss, 0.10-mm thick quartz substrate of 0.75 mum of elevated gold corresponding to three skin depths. The design is compared to more conventional RF technology using a low energy, high power electron beam and to higher energy, lower power Smith Purcell gratings and free-electron-lasers (FELs). The FDTD results show narrow-band, 80% radiation efficiency with a dipole-like radiation pattern - enhanced by adding periods. Radiated power was calculated using two different techniques that agreed quite well i.e. by integrating the far-field Poynting vector as well as subtracting the output from input power.