Modeling and Simulations of Metamaterial based Microwave Devices

Abstract

Dual layer periodically patterned metamaterial inspired antennas on a low cost FR4 substrate are designed and simulated. Some of the designed antennas are also fabricated and tested. Eigen mode dispersion simulations are performed indicating the left handed metamaterial characteristics and are tunable with substrate permittivity. We present the design and simulations of dispersion engineered single unit cell resonant metamaterial (MTM) antenna with proximity feed. The antenna is also investigated with top metascreens made of the same MTM unit cell. The use of metascreens give enhanced antenna performance. A multiband operation with wideband characteristics can be enabled by using proximity type of input feeding. We further simulate, fabricate and test MTM antennas by extending the unit cells along the non-resonant length of the antenna and use a direct type of input feed instead of proximity feed. Again metascreen is applied below the proposed MTM antenna and next used as superstrate above a simple patch to study the effects on bandwidth, gain, efficiency and radiation patterns. The experimental results of these antennas are very good and closely match with the simulations. The radiation patterns are also very good and could be useful in the UWB wireless applications. Next, we present modeling and simulations of an absolute magnifying device in a geometrical sense at microwave frequencies. The device is designed and simulated based on a graded positive refractive index, non-resonant, weakly dispersive region of the I-shaped metamaterial structure at 10 GHz. The structure is simple and easy to fabricate. Its geometrical parameters are varied along with different dielectric powders as a background material, which provide a wide spectrum of graded refractive indices needed for proper device functionality. The complete 30 layer device is first simulated based on I-shape refractive index and then it is simulated with I-shape structure itself inserted into a significant portion of the device. The results show the bending and magnification process reasonably. It demonstrates an Eaton lens like functionality with twice magnification factor.