Archimedean Spiral Antenna Research Articles

Performance enhancement of shorted polygonal archimedean spiral antenna using hybrid reflector

In this paper, performance enhancement in a shorted polygonal archimedean spiral antenna has been proposed by backing it with a hybrid reflector. In the proposed work, two arms of the polygonal spiral antenna are shorted at an outer octagonal conductive ring aiding in size reduction of the polygonal spiral. The shorted polygonal spiral antenna with the advantages of low profile and the good axial ratio at lowest frequencies of operation is backed by a hybrid reflector that utilizes combination ferrite layer which tapers towards the center to a PEC layer. The hybrid reflector helps to improve the gain of the antenna significantly at low frequencies without compromising the gain of the antenna at high frequencies. The antenna operates from 0.6 GHz to 6.5 GHz with a minimum boresight gain of 0.2 dBic at 0.6 GHz and an average gain of 6 dBic from 2.2 GHz. The antenna also demonstrates a good axial ratio of ≤3 dB over the VSWR bandwidth in a low-profile dimension of 0.13 λ0 × 0.13 λ0 × 0.04 λ0. The proposed work thus presents a novel idea to develop a compact high-performance spiral by shorting the arms of a polygonal spiral with a conductive ring and backing the same by a hybrid reflector and cavity.

Simple design of broadband circularly polarized two‐arm Archimedean spiral antenna

This article presents a broadband circularly polarized two-arm Archimedean spiral antenna with a novel simple feeding method. Contrary to the conventional spiral antenna excited by a vertically or horizontally balun, the presented design is directly fed by a coxial cable with a planar feeding section optimized to provide a broadband input impedance matching. An antenna prototype has been fabricated and measured to validate the concept. Measured results of reflection coefficient and axial ratio show a good performance over a frequency range from 1.0 to 3.5 GHz, equivalent to ~111.1%. Within this band, the antenna prototype exhibits bidirectional radiation with broadside gain values of better than 3.6 dBic.

Design of an Archimedes spiral antenna for PD tests under repetitive impulsive voltages with fast rise times

Partial discharge inception voltage measurements under repetitive impulsive voltages play an essential role in evaluating the reliability of inverter-fed low voltage rotating machines. Using impulsive voltages, partial discharge (PD) signals and the disturbance induced by power electronics switches have often similar energy distribution in the frequency domain. Thus, PD test technologies used with sinusoidal voltages are no longer effective. Under repetitive impulsive voltages, ultra-high frequency detection is recommended to couple high-frequency spectral components from the PD and remove the low-frequency disturbance coming from power electronics. However, to obtain high signal to noise (S/N) ratio, the parameters of the antenna used for PD detection should be designed considering the PD and the disturbance energy distributions in the frequency domain. In this paper, we discuss the design and show the properties of an antenna with Archimedes plane spiral structure intended for PD detection under repetitive impulse voltages. The simulation shows that the antenna has low voltage standing wave ratio (<2) and improved directivity in the frequency range from 0.5 to 2 GHz. Moreover, PD tests performed using repetitive square waves with different rise times demonstrate that the designed antenna can receive PD signals efficiently with high S/N.

RF Energy Harvesting System Based on an Archimedean Spiral Antenna for Low-Power Sensor Applications.

This paper presents a radiofrequency (RF) energy harvesting system based on an ultrawideband Archimedean spiral antenna and a half-wave Cockcroft-Walton multiplier circuit. The antenna was proved to operate from 350 MHz to 16 GHz with an outstanding performance. With its use, radio spectrum measurements were carried out at the Telecommunication Engineering School (Universidad Politécnica de Madrid) to determine the power level of the ambient signals in two different scenarios: indoors and outdoors. Based on these measurements, a Cockcroft-Walton multiplier and a lumped element matching network are designed to operate at 800 MHz and 900 MHz frequency bands. To correct the frequency displacement in the circuit, a circuit model is presented that takes into account the different parasitic elements of the components and the PCB. With an input power of 0 dBm, the manufactured circuit shows a rectifying efficiency of 30%. Finally, a test is carried out with the full RF energy harvesting system to check its correct operation. Thus, the RF system is placed in front of a transmitting Vivaldi antenna at a distance of 50 cm. The storage capacitor has a charge of over 1.25 V, which is enough to run a temperature sensor placed as the load to be supplied. This demonstrates the validity of the RF energy harvesting system for low-power practical applications.

An Inner- and Outer-Fed Dual-Arm Archimedean Spiral Antenna for Generating Multiple Orbital Angular Momentum Modes

Orbital angular momentum (OAM) beams have attracted great attention owing to their excellent performances in imaging and communication. In this paper, a dual-arm Archimedean spiral antenna (DASA) is proposed to generate multiple OAM states with positive and negative values by feeding at the inner and outer ends, respectively. The topological charge of radiated vortex waves is reconfigurable by tuning the operating frequency. Dual-mode OAM states are generated at different working frequencies (l = ±1 at 3 GHz, l = ±2 at 4 GHz, and l = ±3 at 4.8 GHz). Both the simulation and measurement results demonstrate that OAM beams can be generated effectively by the DASA. In addition, a conical cavity is used to increase the gain of the proposed DASA for more than 5 dBi in comparison to the traditional cylindrical cavity. Furthermore, the qualities of the generated OAM modes by the proposed DASA have been evaluated at different operating frequencies of 3 GHz, 4 GHz, and 4.8 GHz, respectively. The OAM modes purities of l = −1, −2, −3, 1, 2, and 3 are predominate with the proportion of about 81%, 70%, 74%, 78%, 77%, and 75%, respectively. Our results demonstrate that the proposed DASA has great potentials in OAM multiplexing communication systems.

Radiating a circularly polarized impulse through a dispersive spiral antenna

AbstractA novel method of radiating circularly polarized (CP) impulse through a dispersive spiral antenna is presented. The proposed method utilizes time‐reversal‐based pulse compression to radiate a CP impulse without any modification to the existing antenna design, providing flexibility where the antenna can be used as a normal dispersive spiral antenna when TR is not applied. Using an Archimedean spiral antenna, the proposed method is validated with numerical simulation and measurement.

Enhanced Broadband RF Differential Rectifier Integrated with Archimedean Spiral Antenna for Wireless Energy Harvesting Applications

This work addresses the design and implementation of a broadband differential rectifier (DR) combined with an Archimedean spiral dipole antenna (ASDA) for wireless power harvesting at low incident power densities below 200 W/cm. The proposed design exhibits an improved RF-DC conversion efficiency over a wide frequency range from 1.2 to 5 GHz. This frequency band is associated with several wireless communication services, for instance, ISM, WLAN, 5G, LTE, and GPS applications. The receiving planar ASDA exhibits circular polarization and has an average measured gain of 4.5 dBi from 1.2 to 5 GHz. To enable a wide operating bandwidth, the rectifier circuit is constituted by two architectures, designated A and B. Each scheme is designed to harvest power efficiently across a specific bandwidth. The optimal performance of both rectifiers are obtained using the nonlinear harmonic-balance simulations. The antenna–rectifier integration yields a compact rectenna with a high-efficiency performance over the intended bandwidth from 1.2 to 5 GHz for an input power of 9 dBm and terminal load resistance of 1 k. The total measured RF-DC conversion efficiency is maintained above 30% across the entire frequency range with a peak value of 61% achieved at 1.2 GHz. In comparison with similar architectures, the proposed rectenna maintains a stable output efficiency despite the wide fluctuations in the input frequency and also has a minimum footprint size (58 × 55 mm).

Wideband Monostatic Co-Polarized Co-Channel Simultaneous Transmit and Receive Broadside Circular Array Antenna

A novel wideband monostatic circularly co-polarized co-channel simultaneous transmit and receive (C-STAR) broadside circular array antenna with a partially shared beam-forming network (BFN) is proposed. The configuration consists of four sequentially rotated two-arm Archimedean spiral antennas, backed by a finite ground plane and driven by a BFN. Every two diagonal antenna pairs are fed with differential phases to obtain similar co-polarized broadside transmitting (TX) and receiving (RX) beams. Each individual element has single feeding port and operates simultaneously as TX and RX over the same frequency. The proposed C-STAR approach utilizes antenna orientation, geometric symmetry, and partially shared BFN to overcome self-interference. In the absence of asymmetry and BFN imbalances, complete wideband self-interference cancellation is achieved without relying on time-, frequency-, space-, pattern-, antenna/port-, or polarization-multiplexing. The fabricated prototype has measured TX/RX isolation >38 dB, axial ratio <;3.7 dB, and realized gain between 3 and 8.8 dBic over 1.25-2.5 GHz. The TX and RX radiation patterns are similar with envelope correlation coefficient >0.93.

Cavity-Backed Archimedean Spiral Antenna with Conical Perturbations for 3U CubeSat Applications [Education Corner

This article reports the development of a CubeSat antenna for the 2017 IEEE Antennas and Propagation Society (AP-S) Student Design Contest by an interdisciplinary team of undergraduate and graduate students from the Electrical and Aerospace Engineering Departments of the University of Alabama. First, as satellites require lineof-sight (LOS) communication with the ground station, a link scenario was created to determine the points of visibility in the CubeSat's orbit. Then, link and power budgets were calculated to determine the specifications for an antenna that is suitable for 3U Cube-Sat applications in the X band (8 GHz) and Ku band (11.2 GHz). To meet the requirements, a cavity-backed Archimedean spiral antenna (ASA) with quadruple conical perturbations (QCPs) was designed and fabricated.

A miniaturized ultrawideband Archimedean spiral antenna for low‐power sensor applications in energy harvesting

AbstractThis work presents the design, manufacturing, and measurement of a miniaturized circularly polarized ultrawideband Archimedean spiral antenna that operates from 0.3 GHz to 16 GHz. It acts as a radiofrequency harvester, capturing the energy spectrum in the bands of interest (FM, DTT, LTE‐800, GSM‐900, GSM‐1800, LTE‐2100, WiFi, LTE‐2600 and WiMAX). A prototype of the Archimedean spiral has been manufactured and characterized in the laboratory, and a comparison of the harvested power with respect to other also manufactured baseline 2.4 GHz patch antennas has been carried out in two different locations: inside and outside the laboratory. These results prove that hundreds of microwatts can be acquired in a normal situation, without the spiral pointing directly at a prefixed source.

Miniaturization of Archimedean spiral antenna for wideband beamforming arrays

AbstractThis paper proposes a compact spiral antenna with an improved bandwidth and miniaturized radiator for 3:1 (2‐6 GHz) wideband antenna beamforming arrays. The proposed antenna is composed of an Archimedean spiral antenna (ASA) with an annular ring and additional dielectric substrates with a circular hole. The spiral and ring radiators are printed between two substrates made of FR‐4, with a dielectric constant of 4.5 and thickness of 1.524 mm. The size of the antenna is 30 mm × 30 mm × 3.048 mm (0.2λ × 0.2λ × 0.02λ at the lowest frequency). The reduction rate of size is up to 15% compared with a conventional ASA using an annular ring, and it also has low‐profile characteristics.

Design, simulation, and fabrication of a small size of a new spiral shaped of circular microstrip patch antenna

AbstractThere are many applications in communication and microwave hyperthermia are desirable where small lateral size and narrow band properties. Circular microstrip patch and the Archimedean spiral antenna were combined to affect positively on the performance of the exited antenna. The design includes the selection carefully of the dielectric material, the radius of circular microstrip patch, the empty space through the turned microstrip spiral, the width of the spiral and the number turns of the spiral. The simulation and the experimental results confirm that the small size of combined spiral and microstrip patch antennas can be operated over a wide range of frequencies. In addition to the techniques that are applied to obtain the results such as directivity, Half‐Power Beamwidth, S‐Parameters, and stands for Voltage Standing Wave Ratio (VSWR) for the new shape. The outputs are compared and analyzed with a numerical formulation for spiral and patch antennas and measured.

Hybrid Utilization of Loading Techniques and Cavity Groove for Performance Enhancement of the UWB (2–18 GHz) Spiral Antenna

This paper presents, for the first time, the hybrid use of loading techniques (which involve terminating the spiral arms with different structures to give a resistive or capacitive effect) and a novel technique of cavity groove in order to enhance the performance of two-arm, cavity-backed, 2–18 GHz spiral antenna. The antenna is made on Duroid 5880 and has the smallest form factor (50 mm diameter), meeting all the performance metrics, which are targeted for efficient performance of a spiral antenna for ultra-wideband (UWB) applications. Measured results match the simulated results and show that by the utilization of hybrid loading and cavity groove, the gain is increased by a factor of 3.65 dBi and the axial ratio is improved by 2.73 dB at (2 GHz) as compared to a simple Archimedean antenna made on Duroid 5880, without increasing the size. The proposed antenna shows 2.25 dB more gain and improved axial ratio performance as compared to a simple Archimedean spiral antenna made on Tmm4, without the utilization of the hybrid techniques proposed earlier in the literature.

High-performance broadband vortex beam generator using reflective Pancharatnam–Berry metasurface

Vortex beam generators, especially for broadband working ones, are essential in recent communication systems, since it is believed to be a key to improve the channel capacity efficiently. However, available vortex beam generators surfer from narrow bands, low efficiencies as well as complex configurations. In this paper, we propose an ultra-broadband reflective Pancharatnam–Berry metasurface to generate the vortex beams within 12-18 GHz. The metasurface consists of 20×20 single-layered rotated reflective elements A Ku-band Archimedes spiral antenna is placed at the focal point of the PB metasurface as a feed source which is used to emit a right-handed circularly polarized wave. Then, the metasurface is fabricated, simulated, and measured. Numerical and experimental results coincided well, indicating that the proposed vortex beam generator demonstrated several improvements, including wideband working (12-18 GHz), high efficiency (75.76%), and simple fabrication. Our findings open up a new avenue for the design of high-performance broadband vortex beam generators.

WIDEBAND PLANAR SPIRAL ANTENNA WITH PERIPHERAL FEEDING

The topology of a planar Archimedes spiral antenna with a small number of turns is presented. Its main feature is the peripheral feeding of the spiral, which does not violate the planarity of the structure. On the basis of numerical simulation, the main electrodynamic characteristics for several antenna designs, differing in the number of turns, including the constant and variable width of the tape of the spiral element, are obtained, compared and discussed. The results of the numerical analysis showed that the relative bandwidth defined by the VSWR at the antenna input and by the directivity, reach from 75 to 120 percent.

UWB with Gain Enhancement Archimedean Spiral Microstrip serial Array Antennas for On-board Satellite Communications

UWB with Gain Enhancement Archimedean Spiral Microstrip serial Array Antennas for On-board Satellite Communications

A broadband circularly polarized cavity-backed Archimedean spiral array antenna for C-band applications

In this letter, a new configuration of sequentially rotated circularly polarized (CP) array antenna with a modified gain is investigated. In order to realize the presented antenna, four Archimedean spiral radiators are applied on a substrate, backed by a circularly slotted ground plane. Also a combination of 180° rat-race coupler and 90° branch-line couplers prepare the employed feeding network in this study. Furthermore, cavity-backed structure is utilized to enhance the antenna gain and achieve a directional radiation pattern over the operating frequency band. This configuration also extends the return loss (RL) and the axial ratio (AR) bandwidths, simultaneously. According to the experimental results, the 2×2 CP array antenna has RL bandwidth of 64.28%, AR bandwidth of 54.28%, and peak gain of 10.84dBic. The close correspondence between the measured and the simulated results validates the proposed design.

Polarisation reconfigurable, centre‐fed, and low‐profile Archimedean spiral antennas with unidirectional broadside patterns

A low-profile, dual circularly polarised, and centre-fed four-arm Archimedean spiral antenna with broadside radiation patterns is investigated in this paper. It is shown that both right- and left-hand circular polarisations (CPs) are generated in the four-arm spiral antenna, whose circumference is less than three wavelengths, by properly exciting the spiral arms from their inner ends. Similar analogy can be used to extend the concept to any multi-arm spiral antenna. The proposed compact antenna, which is backed by a planar reflector surface, is designed and extensively investigated to study main antenna specifications including gain, cross polarisation, and pattern symmetry, for dual-polarised wireless communication systems. A 3 dB axial ratio frequency bandwidth of about 1.8–5.3 GHz is realised for both clockwise and counter-clockwise CP with axial beams. Furthermore, superior pattern symmetry with equal beamwidths is attained for both senses of polarisation. A prototype antenna is fabricated and tested. Excellent agreement between the measured and computed results is observed. An asymptotic equation is also developed to estimate the antenna peak gain over the frequency band for both senses of CPs.

A Design of High Gain Archimedean Spiral Antenna

The design of a plane Archimedes spiral antenna is put forward. Compared with the traditional Archimedes antenna, the gain of low frequency is improved by adjusting shape and thickness of the absorber in the back cavity. Thus an Archimedean spiral antenna with the gain of 1.3dBi at the low frequency is designed, which bandwidth covers from 1GHz to 3GHz with return loss less than -10dB. Finally, the designed antenna is made, the results of the measurement fit well with the simulation ones.

Compact Circularly Polarized Archimedean Spiral Antenna for Ultrawideband Communication Applications

A novel compact circularly polarized Archimedean spiral antenna for ultrawideband (UWB) communication applications is presented. The basic structure is a two-arm planar Archimedean spiral antenna, which is fed by a tapered wideband balun. These two arms are extended on the profile and connected together at the end to elongate current path, while four lumped resistors are loaded on them to improve the reflection coefficient at low frequency. A circular reflector with cross slots that consists of one circular slot at the junction of two orthogonal rectangular slots are designed and optimized, which improves the performance of axial ratio (AR). The proposed antenna has a compact size of 36 × 36 × 20 mm3. The voltage standing-wave ratio is less than 2.5 in the frequency range of 1.9–8.5 GHz and the AR is less than 3 dB in the frequency range of 2–6 GHz. Both the simulation and measurement results are presented, demonstrating the UWB characteristics of the proposed antenna for wireless communication applications.