Reflectarray Antenna
Understanding Reflectarray Antennas
Reflectarrays offer an attractive alternative to parabolic reflectors for applications where flat, lightweight, high-gain antennas are needed. Each element is a printed patch designed to reflect with a specific phase, replacing the curvature of a parabolic surface with element-level phase compensation.
Reflectarray Properties
- Profile: Flat surface, typically lambda/10 thick. Much thinner than a parabolic dish.
- Gain: 20-40+ dBi depending on aperture size. Similar to equivalent-area dish.
- Bandwidth: 5-15% for fixed beam. Limited by element phase bandwidth and spatial feed path length variation.
- Manufacturing: Standard PCB fabrication. Low cost compared to shaped reflectors.
Frequently Asked Questions
What is a reflectarray?
A flat antenna surface of printed patches that reflect incident waves with controlled phase, forming a focused beam like a parabolic dish but in a flat form. High gain (20-40 dBi), low profile, PCB manufacturing.
How does it compare to a parabolic dish?
Reflectarray: flat, lightweight, low profile, easy to manufacture, conformal. Dish: wider bandwidth, higher efficiency, proven technology. Reflectarrays are preferred when flatness and weight matter. Dishes when bandwidth and efficiency are paramount.
Can reflectarrays steer the beam?
Yes, with reconfigurable elements (varactors, PIN diodes, or MEMS switches on each patch). This creates an electronically steerable reflectarray. Bandwidth and complexity are the main challenges compared to conventional phased arrays.