Impedance matching of planar antenna array elements for terahertz rectenna.

The terahertz frequency band of electromagnetic radiation has many potential practical uses. However it still remains to be underdeveloped because of the difficulties with its generation and detection. Many modern studies suggest using rectennas (rectifying antennas) as a potential efficient terahertz detector. The application of rectennas in the terahertz band is challenging in its own way. In particular an efficient operation of a rectenna device requires applying high values of voltage to the rectifying element. This can be attempted by employing an antenna array. However the terahertz band is the band in which the effects of finite conductance of metals start becoming noticeable. This means that antennas in the array cannot be spaced too far away from each other. For a terahertz antenna one of the most popular kinds of structure is a planar antenna, placed on top of a dielectric layer with a metal reflector beneath it. Placing connecting wires in the same plane as the antenna array can minimize the length of the said wires. But it also leads to the structure becoming too complex to compute as the number of the antennas in the array increase. Placing the connections in a different plane, e.g. behind the reflector, can eliminate the influence of these connections on the antenna array characteristics. This study shows that this method also allows adding antennas to the array in a unified manner regardless of their amount. It is worth noting that using this way it is also possible to achieve a predictable behavior of the output impedance of the antenna array.