Masoud Khoubroo Eslamloo - Department of Electrical and Electronic Engineering, Urmia Branch, Islamic Azad University, Urmia, Iran
Pejman Mohammadi - Department of Electrical and Electronic Engineering, Urmia Branch, Islamic Azad University, Urmia, Iran
Nasrin Yazdanpanah - Department of Electrical and Electronic Engineering, Urmia Branch, Islamic Azad University, Urmia, Iran
Changiz Gholbadi - Department of Electrical and Electronic Engineering, Urmia Branch, Islamic Azad University, Urmia, Iran

In this paper a 3dB miniaturized broadband branch-line coupler is designed and fabricated. The bandwidth of this coupler is aapproximately 1 GHz from 2 GHz to 3 GHZ. The new shape distributed capacitors placed within the empty space of the hybrid, minimize the size of the coupler also, ground structure was defected for this purpose and increased the operational bandwidth of the coupler. A prototype was designed and fabricated at 2.5 GHz. The outputs have the same amplitude with the 270o phase difference between them. The measurement results corroborate what has been obtained through simulations. The fabricated structure shows 62% size reduction and the bandwidth of 1GHz qualifies this coupler as a good candidate for feeding array antennas, LTE band 7, WiMAX applications and other integrated microwave systems.

Bandwidth, branch-line hybrid coupler, miniaturized hybrid, LTE and WiMAX