Cavity-backed Two-arm Spiral Antenna with a Ring-shaped Absorber for Partial Discharge Diagnosis

Abstract

-A cavity-backed two-arm spiral antenna for partial discharge diagnosis is presented. The proposed antenna consists of a two-arm Archimedean spiral, a tapered microstrip balun as spiral antenna feed, and a ring-shaped absorber-loaded cavity. The Archimedean spiral antenna is designed for the operating frequency band of 0.3 GHz to 1.5 GHz and fed by the tapered microstrip balun. The cavity is utilized to transform the bidirectional beam into a unidirectional beam, thereby enhancing gain. The ring-shaped absorber is stacked in the cavity to reduce the reflected waves from the cavity wall. The proposed antenna is designed and simulated using CST Microwave Studio. A prototype of the proposed antenna is likewise fabricated and tested. The measured radiation patterns are directional to the positive z-axis, and the measured peak gain is 8.13 dBi at a frequency of 1.1 GHz.

Design of a Circularly-Polarized UHF Antenna for Partial Discharge Detection

“…Recently, some researchers studied spiral-type antennas for PD detection [8]- [14]. Various cavity-backed spiral antennas were studied by using inductors [8], resistors [9], a ring-shaped absorber [10], or bow-tie loading [11]. In addition, a spiral antenna was proposed to reduce its size by employing sine-wave meandered arms [12] and an equiangular spiral antenna with a horizontal balun was proposed for easy package [13].…”

A Systematic Approach to Improving the Performance of Spiral Antenna

“…For example, CST MW Studio is used to design and simulate a ring-shaped absorber stacked in the cavity to reduce the reflection of waves from the antenna backing wall cavity. (Kim et al, 2013) The model design and simulation of a tapered multistep matching impedance to a wideband spiral antenna was performed in (Baby and Michael, 2015) using CST MW to obtain VSWR and good gain. CST MW base on finite integration technology (FIT) is used in (Liu et al, 2008).…”

Planar Ultrawideband Circularly Polarized Cosine Slot Archimedean Spiral Antenna for Partial Discharge Detection

“…The UHF spiral antennas reported for PD detection have large aperture (≥ 200 mm) [9], [10], [13]- [15] which limit their use as internal UHF sensor in GIS or window sensor in power transformers. Besides the large aperture size, axial ratio which is an indicator of antenna's circular polarization has not been presented for the UHF spiral sensors widely reported in literature for PD detection [9], [13]- [17]. The circularly polarized ASA reported for PD detection has narrow operating bandwidth of 0.7 to 1.6 GHz and PD detection capabilities were not demonstrated [10].…”

“…Several of the UHF spiral sensors lack the protective radome which provides electrical isolation from the HV environment [7], [9]- [11], [13]- [18]. Lastly, PD detection capability and sensitivity have not been demonstrated for several UHF spiral sensors reported for PD detection [10], [11], [13], [17]. Thus, spiral antennas reported for PD detection have large aperture and do not possess ultrawideband operation, unidirectional radiation pattern and circular polarization in the UHF range which are desirable for PD detection due to multi-path propagation and EM interference in the HV environment.…”