A microwave shutter using conductive polymers

An all solid state electrochromic shutter was made incorporating a conductive polymer to modulate the microwave energy. The active polymer layer was polyaniline doped with camphorsulfonic acid which was switched between its conductive and insulting state using Li+ as the mobile ion and LixMn2O4 as the counter electrode. Changes in the transmission and reflection of X-band microwave energy were measured as a function of time and bias applied between the electrodes. With switching voltages up to ± 3 V modulation of nearly 10 dB was obtained in 10 minutes, but the cycle lifetime was limited.