# How to Construct a Complementary Slotted Two-Arm Spiral Antenna

A method is presented on how to construct and feed a complementary slotted two-arm spiral antenna in CADFEKO.

A complimentary slotted two-arm spiral antenna consists of two spiral slots in a conducting plate. The two spirals are shifted by 180° with respect to one another resulting in spirals of equal width and equal gaps between the spirals.

Spiral antennas are widely used due to their consistent gain and input impedance over a wide bandwidth.