Wide-Band, Forward-Coupling Microstrip Hybrids with High Directivity

Coupled-Line Couplers Based on the Composite Right/Left-Handed (CRLH) Transmission Lines

“…For example, compared with the forward couplers reported in (Deng et al, 2002) and (Lauro et al, 2009), the proposed structure is capable of producing 65% bandwidth enhancement for the amplitude and a 0-dB coupling level with a smaller coupled-line length. Moreover, the proposed structure exhibits broader bandwidth than couplers presented in (Chang et al, 2001;Huang & Chu, 2010;Ikalainen & Matthaei, 1987;Sen-Kuei & Tzong-Lin, 2010;Lauro et al, 2009). Fig.…”

An efficient method for analyzing nonuniformly coupled microstrip lines

“…Coupled microstrip lines are very useful for designing both backward-and forward-coupled directional couplers [11,18,19]. The analysis method described in these studies was applied to a backward coupler in [11], where detailed circuit parameters and experimental results were provided.…”

“…Microstrip codirectional couplers provide an essential component for microwave and millimeter-wave integrated circuits because they can obtain an arbitrary coupling ratio, a broad bandwidth, and good directivity via optimizing the coupling parameters [18,19]. In a codirectional coupler, coupling is proportional to the difference between even-and odd-mode phase velocities, ␤ e Ϫ ␤ o , while in the counter-directional coupler, the coupling is proportional to ␤ e ϩ ␤ o .…”

Design and measurement of microstrip ferrite coupled line circulators

“…Hence these equal impedances are an important discovery, because in theory this eliminates the need for matching tapers at the ports of the FCL to minimise any "backward coupling" [16].…”