Low profile wideband antenna for DECT applications

For mobile and hand portable applications the main attraction of a slot antenna over the more conventional E field antennas is that it is very low profile. This combined with its relatively small overall size, for an equivalent performance of a dipole or an inverted F, make it suitable for situations where conformality with the equipment housing, e.g. a vehicle roof or the body of a handheld telephone, is important. The performance of a resonant λ/2 slot antenna is virtually the same as a λ/2 radiator. The main electrical characteristics of the resonant slot antenna are a vertically polarised (E) field, an omnidirectional azimuthal coverage together with a 1dBd gain in the same plane. In portable equipment it is important to reduce antenna currents in the body of the transceiver since these currents are induced in the hand of the user which results in imbalance and loss (the hand is essentially a saline solution). The resonant annular slot antenna is unbalanced and assuming a reasonable ground plane dimension there is little induced current in the equipment housing (PCB etc.), a desirable characteristic