Phase Velocity Compensation in Parallel-Coupled Microstrip

Ultra-Broadband Directional Couplers Using Microstrip With Dielectric Overlay in Millimeter-Wave Band

“…Some of these techniques are wiggly couplers or sawtooth [9], using anisotropic substrates [10], or using dielectric overlay [11][12][13][14]. The last technique has been selected in this article because it has been considered the more suitable to work at the high frequencies of millimeter-wave band.…”

Compact parallel coupled‐line bandpass filter with wide bandwidth and suppression of spurious

“…In the literature [1][2][3][4][5][6], various approaches have been reported to overcome the aforementioned problems. The defected ground structure (DGS) [1] provides attenuation poles for a wide stopband.…”

“…Some modified coupled-line structures, such as wiggly lines [2] and meandering lines [3], have been used to attenuate the spurious response at 2f o based on a phase velocity equalization procedure. Additionally, capacitors have been placed between the coupled lines [4] to compensate for the difference between evenand odd-mode phase velocities. To solve the problem of wide bandwidth, three-line structures [5] and ground-plane aperture techniques [6] can enhance the coupling between microstrips.…”

“…Various colorless light sources like injection-locked lasers and the remodulated semiconductor optical amplifiers (SOAs) can be utilized in optical network units (ONUs). Alternative light source such as DFB-lasers and optical modulators can be used to provide much higher data rates up to 10 Gbps [3,4].…”

Improvement the Characteristics of the Microstrip Parallel Coupled Line Coupler by Means of Grooved Substrate

“…In another technique, lumped capacitances are added at the ends of the microstrip coupled-line coupler to increase the electrical length of the odd-mode at the design frequency [17]. However, the capacitors values are restricted by the modal phase velocity difference.…”