Investigation of an optically induced superstrate plasma for tuning microstrip antennas

Abstract

Optically induced electron-hole plasmas in silicon are used to perform radiation pattern tuning.The antenna is a slot loaded microstrip patch and the effect of illumination is shown to produce beam switching in the radiation patterns of certain modes while other modes are left unaffected. The structure is specifically designed to make the best use of currently available miniature laser sources to form a compact tunable package. Modelled and measured results for tuning of the radiation patterns and frequency response are presented. The effect of the losses incurred by the plasma along with the losses in the optically transparent ground plane are quantified in both simulation and measurement. This forms the basis for designing other types of optically tunable miniature antennas based on the structure presented.

Non‐linear characteristics of an optically reconfigurable microwave switch

“…This paper shows complete two-tone non-linearity results with 10 W input power per tone which gives excellent performance similar to MEMS devices [5]. This paper also builds on the tunable antenna we developed in [12] where we introduced bottom side illumination through a glass substrate and applies this to a microstrip switch. Bottom side illumination through drilled conventional substrates has been shown previously [13]; however, the use of glass substrates minimises the discontinuity introduced into the microstrip line which will become much more important at higher frequencies where optically controlled switching becomes a very attractive technology.…”

An Optically Controlled Coplanar Waveguide Millimeter-Wave Switch

“…In this case a plasma region made up of electron and hole pairs is created and this area becomes electrically conductive. We have developed several such switches and switchable antennas based on microstrip lines and patch antennas [18][19][20], however microstrip tends not to perform well at millimetre wave frequencies. In particular, CPW reduces surface waves modes and hence reduces dispersion and radiative losses [21].…”