In this article, size reduction and harmonic suppression
in coupled-lines microstrip directional couplers is attained using
dumbbell, and reshaped dumbbell slots, as defected patterns, specifically
placed under the metering position in the ground plane. Quantitative
investigation of the performance of the directional coupler as controlled
by the variations of the DGS rectangular slots height, DGS gap length,
and the DGS reshaped rectangular slot height is presented. This concept
is further illustrated experimentally for a 12 dB coupler realized on RT/
Duroid 5880 substrate. The proposed DGS design confers size reduction
because of the shift of the operating frequency to lower values. The
measurements are in a good agreement with the simulated results and
emphasize the size reduction and the harmonics suppression of the DGS
coupled-lines microstrip directional coupler. |
