Design of a small antenna for wideband mobile direction finding systems

Abstract

In this study, the authors propose a novel small antenna for use in mobile direction finding (DF) systems covering the range 20-1300 MHz. The proposed antenna has a multiconical sleeve to increase the input resistance at low frequencies while reducing the antenna size. A skirt-shaped disk on top of the antenna body maintains the omnidirectional radiation pattern over a wide frequency band without radiation nulls in the broadside direction. The detailed design parameters of the proposed antenna were optimised using a Pareto genetic algorithm (GA) with the FEKO EM software package. Below 200 MHz, the proposed antenna shows a receiving performance comparable to a 60-cm conventional dipole but at only half the size. Above 200 MHz, the antenna maintains an omnidirectional radiation pattern up to 1300 MHz with a stable realised gain, whereas the 60-cm dipole has a broadside radiation null at about 850 MHz.

An Active 20-MHz to 2.5-GHz UWB Receiver Antenna System Using a TEM Horn

“…The TEM horn antenna as well as the NIC circuit are fabricated, and the results of the measurements are reported in the following. Table I compares some parameters of the present work to similar works to the best of the knowledge of the authors [6]- [8]. As can be seen, the proposed antenna system has the following advantages: 1) it has the largest fractional bandwidth thanks to the active matching circuit; 2) it has both a very wide bandwidth and a good return loss; 3) only one antenna is used to cover the whole operational bandwidth, unlike the others.…”

Rounded‐edge bow‐tie antenna for wideband mobile direction finding system

“…For an unambiguous AoA estimation, a should be smaller than the half wavelength of the highest frequency of the incident wave if not multiple AoA's can produce the same phase difference in multiples of 2π. On the other hand, smaller antenna distances a decreases the phase resolution for the lower frequencies and increase AoA errors [27][28][29]. The AoA is computed using correlative interferometer algorithm in computation process as shown in Fig.…”

Miniaturized LPDA Antenna for Portable Direction Finding Applications

“…In most portable DF systems, a low-noise amplifier (LNA) with 15-dB to 20-dB gain is usually installed at the input of the DF antenna to detect weak signals [6]. In this work, the design specifications of a miniaturized LPDA antenna are chosen as a realized gain greater than 2 dBi and a front-to-back (F/B) ratio greater than 10 dB considering the miniaturization and the LNA gain.…”