Miniature Folded Printed Quadrifilar Helical Antenna With Integrated Compact Feeding Network

Abstract

A miniature folded printed quadrifilar helical antenna (FPQHA) using a novel compact feeding network is proposed. Folding and meandering techniques are used to obtain 66% of size reduction for the axial length of the printed quadrifilar helical antenna. A compact feeding network using an out-of-phase power divider based on double-sided parallel-strip lines and a Wilkinson power divider is designed. A fabricated prototype of the FPQHA employing the compact feeding network is presented. The measured positive gain bandwidth is from 380 MHz to 425 MHz with a reflection coefficient less than −20 dB and an axial ratio below 2 dB. The measured maximum gain is 3.08 dBic at 395 MHz with a half-power beamwidth of 150 •. With good radiation performance and integrated feeding network, the proposed antenna can become a better candidate in satellite and mobile communications.

Steerable miniaturised printed quadrifilar helical array antenna using digital phase shifters for BGAN/GPS applications

“…To simplify the design and miniaturise the antenna structure, the input impedance of each arm of the antenna has been optimised to be 50 Ω; hence, no matching circuit is needed in this interface. Additionally, to design a 1:4 splitter in the feed network, we used two Wilkinson power dividers placed on top of each other using a multi-layer board fed by a balun [9]. Microstrip Wilkinson splitters are connected to a double-sided parallel-strip line with an inserted ground plane balun to provide a 180° phase difference between the two splitters as shown in Figs.…”

“…Alternatively, resonant axial mode printed quadrifilar helical antennas (PQHAs) [8,9] are particularly attractive for GPS/BGAN applications, as they offer small size, CP radiation, and wide-angle coverage in the elevation plane. Each PQHA is composed of four equi-spaced parallel line radiators with an optimised pitch angle that are wound in a clockwise or counter-clockwise manner depending on the polarisation sense/lobe direction required.…”

Dual-Helix Monopole Antenna With Circular Polarization Operation for Minimally Invasive Surgery System

“…Meanwhile, the loss caused by the multi-path effects between the transmitter and the receiver can be reduced by using the circularly polarized (CP) antennas. The various antennas with CP proposed in the literature so far include a compact microstrip antenna fed by an orthogonal 3 dB directional coupler with 90 • phase difference [11], a combination monopole/quadrifilar helix antenna [12], a miniature folded printed quadrifilar helical antenna (FPQHA) [13], and a dual-band CP monopole antenna with shorted strip sleeves [14]. However, the above CP antennas are designed with the common limitation of large size (e.g., [11,14]) and/or complex structure (e.g., [12,13]).…”

“…The various antennas with CP proposed in the literature so far include a compact microstrip antenna fed by an orthogonal 3 dB directional coupler with 90 • phase difference [11], a combination monopole/quadrifilar helix antenna [12], a miniature folded printed quadrifilar helical antenna (FPQHA) [13], and a dual-band CP monopole antenna with shorted strip sleeves [14]. However, the above CP antennas are designed with the common limitation of large size (e.g., [11,14]) and/or complex structure (e.g., [12,13]). Moreover, highly compact antennas are increasingly required for the practical minimally invasive devices Therefore, in this article, a novel dual-helix monopole antenna with circular polarization operation is proposed for ISM wireless communication.…”