A 6.5 - 50 GHz battery-powered compact rotary joint for polarization ellipticity measurements

A simple, efficient, and compact rotary joint has been designed, realized, and measured. It has been used intensively to perform polarization ellipticity measurements on various circularly polarized antennas (e.g., helical antennas and circularly polarized horns, used either individually or feeding a lens antennas) operating in millimeter-wave band (similar to 30 GHz). (C) 2010 Wiley Periodicals, Inc. Microwave Opt Technol Lett 53:375-379, 2011; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.2569

TOLPA (Tripod Omnidirectional Low Profile Antenna): a vertically polarized antenna with 90% bandwidth

A new vertically polarized omnidirectional antenna, inspired by an old design, has been studied, optimized, realized and measured. With a radiation pattern similar to the classical monopole on a ground plane, the proposed antenna concept provides a much larger bandwidth and a very low profile. This antenna has numerous potential applications for mobile communications, UWB and others

Soft and Flexible Antennas on Permittivity Adjustable PDMS Substrates

This work presents novel techniques for producing substrates for flexible antennas. The technique we propose is based on the use of an already existing and widely used substrate material Polydimethylsiloxane (PDMS), where the dielectric properties of the substrate are adjusted by loading the PDMS with low or high permittivity inclusions. The low adhesion characteristics of PDMS are overcome by immersing the conducting parts of the antenna inside the substrate, at the same time sealing the antenna against the influence of dust, or water. A patch antenna prototype is realized and characterized. The built antenna is soft and flexible and it shows good radiation characteristics in terms of input matching and total gain. Measurements are in a good compliance with the simulation results

Novel thin and compact H-plane SIW horn antenna

The substrate integrated waveguide (SIW) technology allows to construct several types of commonly used antennas in a planar way. However, some practical constraints limit their performances when frequencies below 20 GHz are considered. In the case of SIW horn antennas, the available substrates are much thinner than the wavelength yielding to poor matching and undesired back radiation. In this paper, an innovative structure to overcome these limitations is presented. It consists of a transition printed on the same SIW substrate, which improves both the radiation and the matching performances of conventional SIW horns. The horn shape is also further optimized by reducing its dimensions required for a given directivity. This is obtained by modifying the horn profile in order to effectively combine different TE modes. Guidelines are provided to design this type of thin and compact SIW horn antenna. They were applied to manufacture a prototype in the Ku-band with a substrate thinner than lambda(0)/10. Measurement results validate the proposed concepts showing excellent performances

A printed transition for matching improvement of SIW horn antennas

The substrate integrated waveguide (SIW) technology allows to construct several types of commonly used antennas in a planar way. However, frequency limitations associated to commercial substrates appear in the implementation of certain types of antennas, e.g., SIW horn antennas are not well matched when the substrate thickness is much smaller than the wavelength. A printed transition is proposed to overcome this problem. Differently from current solutions, no bulky elements are required allowing to maintain the most important features of this technology namely its compactness and ease of manufacturing. In order to quickly analyze and design the transition, both a coupled resonator and a transmission line models are developed, together with design guidelines. The proposed transition is designed to match a H-plane SIW horn antenna built in a thin substrate (thickness < lambda(0)/10) at different frequency bands at the Ku-band. Experimental results for 3 different transitions show that the matching characteristics are efficiently improved compared with the conventional SIW horn antenna and validates the proposed models