Interferometric direction-finding antenna array with multiplexed/switched radiating elements

A direction-finding antenna, comprising:

• a first set of radiating elements configured to radiate at a first wavelength (λ1), wherein the first set of radiating elements defines a first circle having a first radius with a first phase center distance between 0.15λ1 and 0.20λ1;
• a second set of radiating elements configured to radiate at a second wavelength (λ2) that is shorter than the first wavelength (λ1), wherein the second set of radiating elements defines a second circle having a second radius with a second phase center distance between 0.15λ2 and 0.20λ2, the second radius of the second circle is smaller than the first radius of the first circle, and the second set of radiating elements includes smaller radiating elements than the first set of radiating elements, wherein the first circle and the second circle are concentric;
• and
• a plurality of switches coupled to respective radiating elements of the first set of radiating elements and the second set of radiating elements, the plurality of switches configured to selectively couple selected radiating elements of the first set of radiating elements or the second set of radiating elements to a radio frequency (RF) feed line
• wherein the plurality of switches is configured to sample all the radiating elements in a selected set simultaneously or at least partially in parallel.