Even-odd mode of a double-Lorentz metamaterial and its application to a tri-band branch-line coupler

• Main Authors: Mazeh Fatima, Ayad Houssam, Fadlallah Majida, Joumaa Kassem, Jomaah Jalal, Ndagijimana Fabien
• Format: Article
• Language: English
• Published: EDP Sciences 2016-01-01
• Series: EPJ Applied Metamaterials
• Subjects: Coupler; Double-Lorentz transmission line; Even mode; Metamaterial; Odd mode; Tri-band component
• Online Access: https://doi.org/10.1051/epjam/2016006

The theoretical approach of a double-Lorentz (DL) transmission line (TL) metamaterial using even-odd mode analysis is presented for the application to a tri-band Branch-Line Coupler (BLC). This BLC is based on double-Lorentz (DL) transmission line (TL) metamaterial to achieve the tri-band property. The tri-band operation is achieved by the flexibility in the phase response characteristic of such transmission line. Since metamaterials are in symmetric form, this analysis utilizes superposition and circuit symmetry to solve for the structure’s scattering parameters. A design example of a triple band quarter wavelength DL TL suitable for GSM-UMTS applications is designed and evaluated by simulation using even-odd mode analysis to validate the proposed methodology at circuit level. Then, this simulated DL TL is used in the design of a tri-band BLC which is also being analyzed using even-odd mode analysis. This coupler exhibits transmission of 3 ± 0.5 dB, return losses and isolations larger than 14 dB, and a phase difference of ±90 ±3.5°.