Abstract
Weakly coupled directional couplers are known to have poor directivities and narrow bandwidths. In order to improve both parameters simultaneously, this article demonstrates for the first time, that combination of shunt reactive loading and external impedance matching, results in high directivity, and wideband performance. The proposed directional coupler, fabricated on a Rogers 6035HTC substrate, demonstrates directivity greater than 20dB over a fractional bandwidth of 35%, which is the highest reported for microstrip based design having weak coupling factor of 30dB.