Rigorous Approach for Design of Differential Coupled-Line Directional Couplers Applicable in Integrated Circuits and...

Area of Science:

• Electrical Engineering
• Electromagnetics
• Microwave Engineering

Background:

• Differential coupled-line directional couplers are crucial components in microwave circuits.
• Designing these couplers in multilayer dielectric structures presents unique challenges.
• Existing design techniques may not fully address the complexities of multilayer configurations.

Purpose of the Study:

• To develop and validate a rigorous design procedure for differential coupled-line directional couplers in multilayer dielectric structures.
• To extend scattering parameter analysis to eight-port networks and leverage symmetry properties.
• To experimentally verify the performance of designed 3-dB and 8-dB couplers.

Main Methods:

• Utilizing numerically calculated per-unit-length parameters of coupled transmission lines.
• Extending multimode scattering parameter techniques to eight-port networks.
• Applying nodal to mixed-mode conversion for scattering parameter measurements.
• Designing and experimentally evaluating 3-dB and 8-dB coupled-line directional couplers.

Main Results:

• A validated design procedure for differential coupled-line directional couplers in multilayer dielectrics.
• Demonstration of symmetry properties in eight-port coupled-line networks.
• Experimental confirmation of designed 3-dB and 8-dB coupler performance.
• Successful application of scattering parameter conversion for model evaluation.

Conclusions:

• The proposed rigorous approach enables accurate design of differential coupled-line directional couplers in multilayer structures.
• The extended scattering parameter method and symmetry analysis provide valuable insights.
• Experimental validation confirms the efficacy of the design methodology and measurement techniques.