A novel design of dielectric rod antenna is presented here. Compared to the conventionally used tapered dielectric antennas, this configuration is capable of producing higher gain for a given length of the antenna. The design of an antenna using the new configuration having a gain of 16.7 dBi at 5.6 GHz is discussed. The length of this antenna is 2.3 , which is considerably less compared to the conventional design. The material used for the antenna is Teflon. Along with the detail simulated results, the measured results of the fabricated prototype antenna are also presented.

Design of Short Axial Length High Gain Dielectric Rod Antenna

A feed assembly for an antenna having a non-circular reflector, in which the feed assembly includes a feed horn capable of correcting the distortions of circularly polarized signals caused by the non-circular reflector profile, and wherein the feed horn is coupled with a polarizer that is field-switchable between linear and circular polarization modes of operation. The feed assembly can include a second receive-only feed located in close proximity to the feed horn for communication with adjacent satellites.

Feed assembly for multi-beam antenna with non-circular reflector, and such an assembly that is field-switchable between linear and circular polarization modes

A novel antenna integrated the advantages of the Yagi–Uda and the dielectric rod antenna (DRA) is presented in this communication. The antenna mainly consists of a tapered printed Yagi–Uda, a tapered dielectric cover, and a periodic dielectric rod. First, a tapered printed Yagi is designed as the primary feeder and embedded inside a tapered dielectric rod to improve the directive gain, radiation efficiency, and sidelobe levels. The influence of the dielectric cover to the Yagi is discussed. Then, a dielectric rod with triangular periodic surface is also loaded to the end of the dielectric cover to obtain higher gain and better front-to-back ratio. Finally, a sample of the antenna working at 8.5–9.7 GHz with 18 dBi maximum gain and −23.37 dB sidelobe level is designed. A prototype is fabricated and tested; the measured results match well with the simulated. Compared with the traditional Yagi–Uda antenna and DRA with the same length, the presented integrated antenna has higher gain with lower sidelobe level.

A Novel Integrated Yagi–Uda and Dielectric Rod Antenna With Low Sidelobe Level

A slotted waveguide antenna, as part of a wireless battery system for a bone fixation implant called the Echidna Pin is proposed. The antenna has 3-dB beamwidth of 65° in both E- and H-planes and its gain is 7.7 dBi at 21 GHz. The proposed antenna is conformal to the body of the pin and uses the pin as a waveguide. It is shown that placing a small Perspex plate after the waveguide launcher allows satisfactory return loss performance at all resonant frequencies as the length of the waveguide changes. The pin is used in distraction osteogenesis and allows the distance between the two surgically broken pieces of bone to be changed, thus expanding both soft tissue and bone volume simultaneously. The wireless battery system allows reception of RF power and eliminates the need for daily manipulations on an externally fitted device, or an operation on the body to change the length of the pin. It also makes the treatment significantly less painful for the patient and reduces the risk of infection.

Wireless Orthopedic Pin for Bone Healing and Growth: Antenna Development

Dielectric rod antennas of circular cross-sections have been numerically investigated. Various structures of finite-length rods are compared as functions of their different physical parameters, such as the rods' diameter, length, dielectric constant, multi-layer and finally the effect of corrugation. The far-field radiation pattern characteristics of these various antennas are presented as well. Results indicate that the operating bandwidth of these antennas can be extended by utilising either a core with a high dielectric constant and a cladding layer with a lower dielectric constant or equivalently a corrugated rod of the high dielectric constant material. The simulation of the various types of rod antennas have been compared with the measurement and very good agreement has been achieved.

Design guidelines for multi-layer dielectric rod antennas fed by Vivaldi antennas

A highly directive antenna of simple and lightweight structure is designed and tested experimentally. It consists of a dielectric rod with conical hole loading an open-ended circular waveguide. The test has shown that three different radiation patterns can be obtained depending on the depth of penetration of the rod inside the waveguide. Also an improvement on the axial gain can be obtained when the flare angles are smaller than 30\deg . The optimum design consists of a rod of conical flare angle of 7.5\deg which results in an improvement of 5 dB over the unloaded waveguide accompanied with a beamwidth which is half that of the unloaded structure. One practical application of the proposed design is its use as a feeder for parabolic reflectors, the advantage being the sharp nulls on both sides of the main lobe which will result in minimizing edge diffraction.

G. Martens

Papers

A dielectric-loaded circular waveguide antenna