Proof of Concept of a Dual-Band Circularly-Polarized RF MEMS Beam-Switching Reflectarray

Reconfigurable Reflectarrays and Array Lenses for Dynamic Antenna Beam Control: A Review

“…Here we summarize a slightly more general formulation for RRAs [74] (the case of the lens array is available elsewhere [27]). …”

“…This was proposed as early as the 1970's by integrating diodes in a rotation-invariant geometry [73], so that selectively actuating some of the lumped elements implements the 'electromagnetic rotation' of the element. An example is illustrated in Figure 5(a), where the rotation of a dipole is implemented [38] by switching the desired pairs of branches (slots [10] and metal split rings [74] have also been used). Figure 5(b) shows a full array implementation of the concept.…”

“…However, multi-band operation in beam-scanning reflectarrays has only been recently considered. A first proofof-concept of such an operation mode was recently provided considering CP for both frequencies [74], as depicted in Figure 8. This was based on the element rotation technique described in Section IV-C, using MEMS to electronically implement the required rotation at each cell while preserving low loss at the operating frequencies 24 GHz and 35 GHz.…”

“…8. Principle of a reflectarray for independent beam-scanning of two CP beams at different frequencies in the millimeter wave range [74]. (a) scanning is achieved by independently rotating slip-ring elements corresponding to each frequency using MEMS switches (b) measured switched-beams on frozen prototypes at the two operation frequencies.…”

Frequency Agile Radial-Shaped Varactor-Loaded Reflectarray Cell

“…For example, many reflectarray configurations, among those described in [2], [3], offer polarization flexibility, frequency agility or multi-band operation through the use/integration of one or more active components, such as MEMS and PIN/varactor diodes. A dual polarized reflectarray cell loaded by two varactor pairs has been proposed in [7], while a first proof-of-concept of multi-band reflectarray has been reported in [8]. A reflectarray element based on the use of a couple of PIN-diodes and a varactor has been presented in [9], to tune the element reflection phase within a wide frequency range.…”