This paper presents an element of a 2×2-element array antenna for Inmarsat BGAN/GPS applications. The element is an axial mode printed quadrifilar helical antenna that has been integrated with a compact feed network to provide sequential phase rotation for circular polarization (CP) radiation. The novel integrated lumped-element feed network is designed to provide a balanced RF power to the fou...

Abstract—A folded printed quadrifilar helical antenna (FPQHA) with an integrated and compact feeding network is proposed. The axial length of the proposed antenna is miniaturized of about 54.7% than the conventional PQHA by folding the helix arms into several elements. A T-junction power divider combining with two Wilkinson power dividers is utilized to feed the antenna. A fabricated prototype ...

Quadrifilar helix antennas have very interesting characteristics. For instance, by selecting properly the height and number of turns of the helix, one can achieve a radiation pattern of so-called ‘iso-flux’ shape with high gain at low elevation. Such a pattern enables to improve the link budget for stratospheric balloons telemetry as the gain of the antenna compensate for the free space propaga...

Octafilar helical antenna (OFHA) is proposed for handheld ultra‐high‐frequency (UHF) radio frequency identification (RFID) reader. The investigated antenna configuration consists of OFHA placed on reader device in the presence of human hand model. The antenna is designed at UHF band centered at 915 MHz. The antenna return loss, axial ratio, gain, co‐polarized and cross...

Octafilar helical antenna (OFHA) is proposed for handheld ultra‐high‐frequency (UHF) radio frequency identification (RFID) reader. The investigated antenna configuration consists of OFHA placed on reader device in the presence of human hand model. The antenna is designed at UHF band centered at 915 MHz. The antenna return loss, axial ratio, gain, co‐polarized and cross...

in some mobile systems, intelligent antennas are used to increase efficiency in a wide frequency band and different environmental and electromagnetic conditions. environmental factors, such as position of nearby objects, antenna mobility and even user type, can vary the antenna input impedance appreciably. therefore, it is necessary to incorporate an adaptive impedance matching circuit between ...

in this work, a design of quadrifilar helical antenna with characteristics of compact, wideband and circular polarization is presented. It is achieved by combining the ways of tuning the different dimensions of the pairs of bifilars, and a feeding structure for providing the self-phasing technique. Both of simulated and measured results are reported in this study.