Antenna-coupled Schottky diodes for millimeter wave receivers

One of the most critical tasks in the creation of communication and imaging systems in the millimeter wavelength range is the creation of miniature receiving modules, including an antenna and nonlinear element. These modules can be a dipole planar antenna loaded directly by the detector diode (rectenna). For increasing the effective area the receiving rectennas can be coupled in arrays. In this work a microstrip log-periodic rectenna was formed by photolithography on a dielectric substrate and microwave diode 3A147B was mounted directly in the arms of it. A metal screen layer was deposited on the back side of the substrate. An investigation of the radiation pattern (RP) of the rectenna with different dielectric thicknesses and in 42-45 GHz frequency range shows that in the absence of the screen, the RP is rather wide (/spl sim/60/spl deg/) and very nonuniform, the position of maxima and minima depending on frequency. This results in a strong frequency dependency of the response when the antenna is stable.