Gain manipulation of a slotted sphere using general bi-isotropic coating

Area of Science:

• Electromagnetics
• Materials Science

Background:

• Antenna gain is crucial for efficient wireless communication.
• Bi-isotropic (BI) and Tellegen materials offer unique electromagnetic properties for manipulating wave propagation.

Purpose of the Study:

• To investigate the gain characteristics of a slotted sphere coated with bi-isotropic (BI) and Tellegen materials.
• To analyze how coating parameters influence the radiation pattern and forward gain.

Main Methods:

• Numerical calculations were employed to study the gain.
• An eigenfunction expansion method was used to derive analytical expressions for electromagnetic fields.

Main Results:

• Lossless BI coatings yield the highest forward gain compared to dielectric, Tellegen, or chiral coatings.
• Tellegen coatings can reduce forward gain unless the Tellegen parameter is near unity, where maximum forward gain is achieved.
• Coating thickness significantly impacts the gain of realistic BI coatings relative to dielectric coatings.

Conclusions:

• BI and Tellegen coatings offer tunable control over antenna gain characteristics.
• Lossless BI coatings are promising for point-to-point communication systems requiring high forward gain.
• Careful selection of coating properties and thickness allows for tailored antenna performance.