Open Access

Paul Tcheg, David PouhèORCiD

• Although spiral antennas have undergone continuous development and refinement since Edwin Turner conceived them in 1954, only a few compact planar arrays exist. The shortcoming is even more significant when it comes to spiral antenna arrays in mode M2 operation. The present work addresses this issue, among other things. It presents two planar arrays of spiral antennas operating in the same frequency band and radiating for the first one an axial mode M1 and a conical mode M2 for the second. Both arrays are modeled, simulated, and fed with a corporate feeding network embedded in a dielectric substrate. It is shown that keeping the same topology, the array for conical M1 mode can be obtained from the array for mode M2 by a simple introduction of a phase shift on one branch of the feed and vice versa, providing thus the possibility to obtain in the same structure a spiral antenna array operating in both modes in the same frequency band simultaneously. Comparison between simulated and measured data shows good agreement.