Analysis of a cavity-backed annular slot antenna with one point shorted

An L-band, circularly polarized, dual-feed, cavity-backed annular slot antenna with wide-angle coverage

“…The antenna operates in the L-band around a center frequency of 1.6 GHz and yield wide-angle coverage. It is possible to obtain circular polarization with only a single feed by employing various perturbations to the slot [1] or by shorting the slot [2], however, such solutions are usually associated with low axial ratio bandwidths and instead two feeds in phase quadrature are used. Similar antennas, though of different implementation, were previously reported in [3,4].…”

A cavity-backed broadband circularly polarized slot/strip loop antenna with a simple feeding structure

“…This is particularly important for applications in antenna arrays. Many types of slot configurations have been developed for producing circularly polarized (CP) radiation, such as annual slot [3], dual-spiral slot [4], rectangular slot [5], and cloverleaf slot [6]. However, these slot antennas have a narrow axial ratio (AR) bandwidth (usually <5% for AR 3 dB).…”

A mechanically stable, low profile, omni-directional solar-cell integrated antenna for outdoor wireless sensor nodes

“…Annular slot loop antennas, ASA, can have similar radiation characteristic to a monopole antenna on a planar surface parallel to ground, thus dramatically reducing the antenna profile. However, since a shorting across the slot would tilt the radiation pattern towards one direction [3], an ASA cannot operate as desired when placed in the same board space under the solar cell circuitry. Several solar antenna integration methods have been published to this date [4]- [5], but all of them are for ground to space applications where a directive antenna is favorable.…”