P.O. Afanasiev - Post-graduate Student, Southern Federal University
V.F. Sledkov - Ph.D. (Phys.-Math.), Leading Research Scientist Southern Federal University
M.B. Manuilov - D.Sc. (Phys.-Math.), Professor, Southern Federal University

A new modified ultra-wideband in-phase power divider for frequency band 2-18 GHz has been designed, successfully fabricated and tested. The power divider is based on the coupled strip-lines. Only two balanced resistors are used in the proposed structure. So the power divider has very low insertion loss. The capacitive strips placed over the resistors have been introduced in the suggested design as the novel elements. Due to the introduced capacitive strips the isolation and impedance matching of the divider outputs were improved at the high frequencies. The conducting capacitive strips are placed at the opposite side of the dielectric board and they are parallel to the resistor. The edges of the strips are located over the output strip-lines, in that way the capacitive coupling is arisen between the strips and output strip-lines. As a result, the additional capacitive impedance which is connected in parallel with the resistor decreases the total resistor impedance. The conductive strips have an effect on the odd mode only and they improve the impedance matching between the resistor and output lines. On the other hand, it was proved theoretically and experimentally, that the isolation of output lines is improved at the high frequencies of the operational band. The manufactured power divider shows very high measured performances (amplitude imbalance is ±0.2 dB, phase imbalance is ±5, insertion loss is 0.4 dB, isolation is -18 dB, VSWR = 1.5).