Compact Stub Quadrature Coupler

Directional couplers are quite common in microwave technology. One of the main disadvantages of such devices is their large dimensions at low frequencies, and the lower this frequency, the more the question of miniaturization of their dimensions arises. However, along with a decrease in the dimensions of the coupler, its operating frequency band decreases. Therefore, a compromise option was proposed in this work, in which only one pair of quarter-wave segments was replaced by T-structures equivalent in frequency characteristics. This made it possible to reduce the dimensions of the device by 78.6% compared to the standard design, while the frequency band narrowed by only 0.6%.