Traditional Frequency selective surface (FSS) structures have been used for variety ap-plications over the years. With the development of efficient computational methods, more sophisticated approaches based on genetic algorithm have been proposed for optimization of the fixed parameters in FSS design. The demand for FSS structures with miniaturized elements, on the other hand, is on the rise. In practice, FSS surfaces have finite Loop-Wire Design Draft 2 dimensions. This by itself recalls the truncation effects or edge ef-fects, which can degrade the FSS response. Consequently, in order to get a desired re-sponse, the fabricated design must include many elements or unit cells. It should also be noted that the frequency selective properties of the traditional FSS surfaces are resulted from mutual interactions of the periodic FSS elements. Therefore, to observe the desired frequency selective behavior a large number of unit cells must be present. Additionally, for some applications, in contrast, the FSS size needs to be small.
Researchers at the University of Michigan have developed a new, tunable, highly minia-turized-element frequency selective surface (MEFSS). Unlike traditional FSSs, the unit cell size of this design can be as small as λ0/12, which is a factor of 6 reduction in size compared to a typical traditional FSS. The salient feature of MEFSS structures is that their property is localized and thus suitable for moderate size antennas at low frequencies. High-order frequency response is accomplished through establishing a proper magnetic and electric coupling between the inductive and band stop surfaces of the substrate.
Applications and Advantages
- Antennas at lower frequencies
- Other communication and radar applications
- Very small size
- A wide tuning range with minima loss of performance from 6GHz -10GHz