Design of Directional Couplers, Taking into Account the Different Permittivity of the Board

The research in this article will be of interest to specialists working in the field of microwave technology. We offer directional coupler designs that are small in size and perform the function of power sharing. In this case, the couplers are made taking into account the different permittivity of the substrate - 2; 3.38 and 5.2. Compared to standard designs assembled on quarter-wave segments, it was possible to reduce the dimensions of the device by more than 75% by replacing the segments with structures with similar characteristics. It should be noted that the influence of the permittivity on the results of device miniaturization was studied at a fixed substrate thickness. Also, according to the results obtained, it can be observed that with an increase in the dielectric constant, the possibilities of miniaturization decrease, which may be due to the fact that with an increase in the dielectric constant, the classical design of the coupler initially has a smaller area.