First Test of a Photonic Band Gap Structure for HAYSTAC

Abstract

Haloscopic axion searches require the tuning of a TM mode in a microwave cavity. Traditional cavities contain many unwanted modes which can result in mode crossings, ultimately reducing the effective tuning range of a cavity and slowing scan rates. Photonic band gap (PBG) structures have the potential to create resonators without TE modes, allowing for uninterrupted tuning. A tunable PBG structure has been designed for HAYSTAC. A prototype has been built and tested to validate simulations. Results of the fixed frequency case will be shown as well as details of the expected tuning.