Four-arm 2nd- mode slot spiral antenna with simple single-port feed

Abstract

The design and performance of a novel 4-arm equiangular slot spiral antenna operating in the 2nd mode are discussed in this letter. A straightforward feeding method consisting of a single vertical coaxial probe and no underlying mode forming network is proposed. Along with inherent simplicity, this feed enables design flexibility with respect to the slot-to-metal ratio, growth rate, and other spiral parameters. Numerical tools including an in-house finite element-boundary integral (FE-BI) code and Ansoft HFSS are used in designing the antenna. Good performance over an octave bandwidth is achieved, with axial ratio and WoW less than 3 dB, nominal gain of 3 dBic, and VSWR less than 1.6. Performance is verified with measurements. A method for increasing the bandwidth up to 3 : 1, which is the theoretical value determined by the excitation of the first higher order mode, is demonstrated computationally.Index Terms-Log spiral antennas, slot antennas.

Compact cavity‐backed four‐arm slot spiral antenna

“…A chip resistor is placed at the end of the feeding ring to absorb the nonradiated power. Adjusting the sizes of slotted openings to make sure the power coupled to the slotted openings has the same amplitude, so that the 4-arm slot spirals can operate at the 1st-mode [6]. The antenna arm is characterized by Archimedean spiral function r ϭ r 0 ϩ a, where the growth rate is a ϭ 3.45 ͑mm/radian͒, inner radius r 0 ϭ 18.8 mm, and outer radius 45.8 mm.…”

“…Cavity-backed slot antennas can be conveniently fed by various transmission lines, such as rectangular waveguide [2,3], coaxial probe [4], microstrip line [5][6][7][8], and coplanar waveguide (CPW) [9]. Among them, the planar feed lines (microstrip line and CPW) are gaining popularity in the recent years.…”

Dual-Band Dual-Polarized Spiral Antenna for Chinese Compass Navigation Satellite System

“…Circularly polarized antennas are more attractive because linearly polarized receiving antenna can only receive part or none of the circularly polarized signal, which significantly lowers the antenna's efficiency [6,7]. Consequently, many broadband and dual-band circular-polarized planar spiral antennas have been reported [8][9][10]. In [11], a single-arm spiral antenna is presented which can achieve dual-sense circular polarization by feeding at either the inner or outer spiral end.…”

Monofilar Spiral Slot Antenna for Dual-Frequency Dual-Sense Circular Polarization

“…Double, triple and quadruple-arm spiral structures have realized wider CP bandwidths [8]- [10] and dual frequency spiral antennas [11] have been realized. Furthermore a single-arm spiral strip antenna has been reported which can achieve dual-sense CP by feeding either at the inner or outer spiral end [12].…”