Analysis of aperture coupled Multilayered Microstrip directional coupler

The present work describes the design and analysis of a four aperture and six aperture coupled multilayered microstrip directional coupler. The single layered four aperture and six aperture directional coupler consist of two microstrip layers one with ground plane. This comparison shows that the coupling of -10 dB was achieved with the four aperture directional coupler but the higher isolation has been achieved with the new six aperture microstrip directional coupler as compared to four aperture directional coupler. The proposed directional coupler has been designed and analyzed using IE3D software completely on experimental basis. Variation of the performance of the coupler with frequency has also been investigated. Analysis and design procedure of such high directivity asymmetric couplers consisting of various planar and layered structures are presented together with the experimental results for -10 dB couplers on silica.