Single-arm Spiral Antenna Research Articles

A miniature capsule endoscope based on spiral antenna with wireless sensing capabilities

Abstract In this paper, a capsule endoscopy system with a sensing function is proposed for medical devices. A single-arm spiral antenna is designed for data transmission and is combined with the voltage controlled oscillator to achieve sensing capabilities. The designed antenna operates at a 900 MHz industrial scientific medical band. By establishing a three-layer cylindrical model of the stomach, it was concluded that the antenna in the stomach has a high peak gain of −1.1 dBi. Additionally, the antenna achieved a −10 dB impedance bandwidth of 5%. The capsule endoscopy was experimentally measured in both actual stomach and simulated environments. The maximum working distance of the capsule endoscope was measured to be 6.8 m. Additionally, the proposed capsule endoscope was tested for its sensing function using solutions with different dielectric constants. Finally, it was confirmed through link analysis that it has good communication capabilities. The results and analysis confirm that the proposed capsule endoscope can be used for examining gastric diseases.

Optical Transparent Broadband Antenna Array Integrated With Polycrystalline Silicon Solar Cells

This letter presents a 4 × 4 transparent broadband single-arm spiral antenna array integrated with polycrystalline silicon solar cells (PSSCs). For the sake of appraising the antenna, a kind of multilayer structure is established, enabling the PSSCs and single-arm spiral antenna array to combine perfectly, which has little influence on antenna performance and solar cell efficiency. The employment of the transparent substrate and meshed antenna increases the optical transparency to 92%. By adopting this kind of structure, the antenna array can achieve a working bandwidth of 1.26–3.2 GHz (2.54:1) and the highest gain of 19.4 dBi. This circularly polarized antenna array can realize wide working bandwidth, high gain, and high optical transparency while being well integrated with solar cells.

A low-profile wideband compressed single-arm spiral antenna array for mid-band 5G beam steering applications

A low profile wideband spiral antenna array is presented for global mid-band 5G beam steering applications. In the global rollout of mid-band 5G, different frequencies have been licensed within each region (e.g. 3.4–3.8 GHz in the EU and 3.7–5 GHz in the USA). Therefore, antenna arrays must be able to cover a bandwidth of 3.3 GHz to 5 GHz to provide true global coverage. Initially, this work presents the design of a wideband compressed spiral antenna that provides an axial beam throughout its operational bandwidth of 3.3 GHz to 5 GHz, enabling beam steering functionality. Then, this antenna has been placed in a 4 × 4 array with a triangular lattice. The proposed spiral antenna array can provide a scanning range of − 40° ≤ θ ≤ + 40° in all azimuth directions with an average back lobe level of less than − 9.5 dB. This development will allow for low-cost integration of 5G systems for global use, such as passenger aircraft, UAVs, drones, and marine and ground vehicles.

Modeling and analysis of the spiral antenna properties for the research of the brain radiatio in the microwave range

This paper investigates a planar single-arm spiral antenna used to measure human brain radiation in the frequency range 3-5 GHz. The investigation is carried out using numerical modeling (finite elements method) by employing ANSYS Electromagnetics Suite 19.2. The model of human brain tissues and the antenna are built in this software. The optimization of antenna parameters is carried out to obtain the best matching and sensing depth. The frequency dependence of the antenna input impedance, reflection coefficient is computed, and the volume distribution of electromagnetic field in the head tissues is obtained. We investigate the influence of the matching layer to the antenna characteristics in the case of the deviation of the electrical parameters of the head tissue top layers. The matching layer is located between the spiral antenna plane and the surface of the head. The additional simulation is carried out by using WIPL-D Pro EM simulator to validate the obtained results. Shabashov E. P., Shabunin S.N., Mrdakovic B. Modeling and analysis of the spiral antenna properties for the research of the brain radiation in the microwave range. Ural Radio Engineering Journal . 2020;4(1):84–99. DOI: 10.15826/urej.2020.4.1.005

Design and Study of a Circular Polarised Conical-Disc-Backed Spiral Antenna for X-Band Applications

Design of a conical-disc-backed circular-polarized Archimedean single-arm spiral antenna is presented in this paper. The antenna operation covers the $X$ -band frequencies ranging from 8 to 12 GHz. The antenna makes use of a very simple structure having the single-arm spiral backed by a cone-shaped metallic disc to achieve high gain, circular polarization, and unidirectional symmetric radiation near the boresight. The diameter of the antenna only measures to 40 mm. The simulated and measured results show that the antenna has a very good impedance matching (better than −10 dB), good right-hand circular polarization (with an axial ratio of ≤3 dB) throughout the frequency range of interest, and offers a maximum peak gain of 11.4 dBiC. The presented $S_{11}$ response and radiation pattern results also show that the antenna offers excellent performance in the $X$ -band with no need of a balun. Antenna usefulness is also established through a detailed parametric study and comparison with a traditional flat disc structure. Compact size, simple design, wide range, and high gain make the proposed antenna design a good choice for radar, terrestrial communications, and satellite/aerospace communications applications.

Broadband circularly polarized spiral antenna array using sequentially rotated technique

A circularly polarized (CP) spiral antenna array for wideband application is presented, which employs a simple single-arm spiral antenna (SASA), as the radiating element. By introducing a small round disc backed near the antenna center and loading a termination resistor, the SASA achieves a wide im pedance bandwidth without a balun circuit and a good axial ratio (AR) performance, respectively. A total of four array elements are used in the 2 × 2 configuration to obtain a higher gain. Particularly, a method of sequentially rotating the elements is used to improve the axial ratio. The array performs an impedance bandwidth for VSWR ≤ 1.5 of 40% ranging from 1.25 to 1.88 GHz, an excellent AR of better than 0.74 dB, and a gain variation from 11.34 to 14.56 dB within the operating band. Measured and simulated results presented for the array confirm its wide impedance, axial ratio, and gain bandwidths. Acceptable agreement between the simulation and measured results validates the proposed design.

Design of a UHF Antenna for Partial Discharge Detection of Power Equipment

A single-arm Archimedean spiral antenna that can be directly fed by a 50 Ωcoaxial cable is investigated in this study. Every antenna parameter is optimized under simulation to make the antenna work in the ultra-high frequency band. The influence of dielectric materials, feed cone angle, and antenna duty ratio is also examined. Partial discharge (PD) experiments on several typical artificial insulation defects are conducted, and a single-arm Archimedean spiral antenna and a typical microstrip antenna are utilized for PD measurement. The PD characteristics of different insulation defects are also analyzed. Results show that the designed antenna is suitable for ultra-high frequency monitoring. The detection sensitivity of the single-arm spiral antenna is superior to that of the ordinary microstrip antenna. The former can be utilized in wide-band measurement fields.

Dual-Band Counter Circularly Polarized Radiation From a Single-Arm Metamaterial-Based Spiral Antenna

A single-arm spiral antenna whose arm is made of a metamaterial (MTM) transmission line having right- and left- handed properties is discussed. This antenna, abbreviated as the 1-MTM-SPA, has an extremely low-profile structure (0.016 wavelength at a balanced frequency of 3 GHz) and does not need a balun circuit. It is predicted that the 1-MTM-SPA will operate as a circularly polarized (CP) antenna, where right-handed CP radiation is obtained within a particular frequency band and left-handed CP radiation is obtained within a different frequency band. Numerical analysis results obtained using two different techniques confirm the prediction for this dual-band counter-CP radiation. The 1-MTM SPA used for the confirmation shows an overlapping gain and axial ratio bandwidth of approximately 7%. The VSWR relative to the Bloch impedance value is less than two within the overlapping bandwidth, as desired. Experimental data are also presented.

한팔 나선 안테나의 길이 및 급전 변화에 따른 편파 및 빔 틸트 특성에 대한 분석

본 논문에서는 한팔 나선 안테나(single arm spiral antenna)의 편파(polarization) 및 빔 틸트(beam tilt) 특성에 대하여 분석하였다. 한팔 나선 안테나는 나선 둘레 길이(spiral circumference length)가 한 파장 길이 이상 길어지면, 안테나의 최대방사 빔 방향이 안테나로부터 수직인 축빔(axial beam)으로부터 틸트되는 특성을 가지고 있다. 이때 나선 안테나의 급전위치(내부, 외부)에 따라 원형편파 (RHCP, LHCP)가 변화 하며, 안테나의 길이 변화에 따른 빔 틸트시 원형편파 특성에 따라 최대 방사 빔 방향이 서로 상이한 방향으로 틸트 됨을 검증하였다. 이러한 한팔 나선 안테나의 전기적인 특징을 이용하여, 단일 안테나로 이중 편파를 갖는 빔 포밍, 다이버시티, 또는 MIMO어플리케이션에 대한 적용 가능성을 확인하였다. In this paper, a single arm spiral antenna has been investigated about the characteristics of polarization and tilt beam. If a circumference length of spiral is bigger than a wavelength, it have a characteristic of varying maximum radiation beam direction. In addition, circular polarizations (RHCP, LHCP) can be variable by the feeding points (inner, outer). Also maximum beam directions tilt in different direction according to the circular polarizations, LHCP and RHCP. These characteristics of single arm spiral antenna are able to apply in the beam forming, diversity, MIMO application which has dual polarization using an antenna element.