Yacouba Coulibaly, Halim Boutayeb and Tayeb A. Denidni

1. Gain Enhancement of a Dielectric Resonator Antenna Using a Cylindrical Electromagnetic Crystal Substrate Yacouba Coulibaly, Halim Boutayeb and Tayeb A. Denidni

2. Outline • Introduction • Antenna Configuration • Simulation Results • Measurements • Conclusion

3. Introduction Advantages of a Dielectric Resonator Antenna (DRA) • Low losses • Reduced sized • High radiation efficiency • High density integration Inconvenient of a Dielectric Resonator Antenna: low gain

4. Introduction (cont.) To improve the radiations characteristics of the DRA, few studies have been proposed: • The DRA has been placed on different ground planes shapes • Coaxially corrugated. • Strip corrugated. • Mushroom-like Electromagnetic Bang Gap (EBG) substrate.

5. Introduction (cont.) Design Objectives • Use a circularly periodic EBG to increase the gain of a cylindrical DRA. • Exciting the fundamental mode • Have the same radiation pattern shapes with or without the EBG substrate

6. Antenna Design Description: • A Dielectric Resonator (DR) : • The DRA has a radius R=15mm, a height hd=10.5mm,and a permittivityεdra=31.5. . • A Coaxial feed line: • The coaxial line is at a distance of 9 mm from the center. • A circular EBG : • Printed on a substrate of permittivity ε2=2.2 and thickness h=3.2mm. • The distance from one strip to the following one is g=2mm. The periods for the strips is Pr2=24.6mm. • The metallic via have a radius a=2mm, and they are disposed with the same transversal period and the same radial period Pr2=23.6mm .

7. Simulated results Simulated return loss (with Ansoft HFSS)of the antenna with and without the EBG substrate

8. Simulated results (cont) Simulated gain (with Ansoft HFSS) of the antenna with and without the EBG substrate • Results: • The gain is increased by 3 dB due: • to the reduction of the surface waves. • to the coupling between the DRA and the circular EBG (mainly).

9. Simulated results (cont) Simulated radiation patterns at 2.25 GHz, in both the E- and H-Plane, with and without the EBG substrate • Results: • The EBG structure improves the gain • The back radiation decrease

10. Experimental results Photographs of the fabricated antenna prototypes DRA alone DRA with cylindrical EBG substrate

11. Experimental results Measured return loss of the antenna with and without the EBG substrate Network Analyzer

12. Experimental results (cont) Measured gain (in an anechoic chamber at INRS) with and without the EBG substrate

13. Experimental results (cont) Measured radiation patterns with and without the EBG substrate H-plane E-plane

14. Conclusion • The gain enhancement of a DRA has beeninvestigated and good performances have been achieved • By adding the EBG substrate, the radiation characteristics have been significantly improved • The coupling between the cylindrical DRA and the reduction of the surfaces waves enhance the gain of the antenna • Perspectives: • Investigation of elliptical EBG structures; • Design of elliptical patch antennas and elliptical DRAs integrated on elliptical EBG substrates, for Satellites communications applications (circular polarization).