A Circularly Polarized Omnidirectional Rydberg Atomic Sensor Using Characteristic Mode Analysis

In this paper, the near field distribution patterns excited from half spiral nanoslits and gratings are investigated. The various near field distribution patterns observed are due to the interference of propagating surface plasmon emerging from the nanoslits or gratings. The half spiral nanoslits are incident with left and right-handed circular polarization. The resulting focal spots are found at different positions for left (LHC) and right-handed circular (RHC) polarizations. This is due to the change in phase difference of propagating surface plasmon waves emerging from the nanoslit when excited by different circular polarizations. The distance between the focal spots for left and right-handed polarizations is λ_spp/2. In addition, the half spiral nanoslit is also illuminated with linear polarization in different rotational angles. This paper also includes the near field distributions that result from the interference of surface plasmon polariton fields with partial spiral shape. It is believed that these interesting field patterns due to different arrangements of nanoslits could be used for trapping molecules, near field imaging and sensing.

Polarization reconfigurable annular ring slot antenna design

A new broadband circularly polarized (CP) metasurface (MS) antenna based on characteristic mode analysis (CMA) is proposed. The antenna consists of 4×4 truncated Γ-shaped unit cells and is fed by an improved slot coupling structure. The characteristic modes required to achieve CP are analyzed by CMA, and the CP performance is improved by changing the characteristic currents distribution. By introducing a stepped slot structure on the slot floor, the bandwidth of the antenna has been further broadened. By loading the microstrip line to feed the MS, left-handed circular polarization (LHCP) can be realized. In addition, the equivalent circuit method is used to explain how the designed MS antenna achieves CP. The overall size of the designed and fabricated MS antenna is 0.72 λ 0 ×0.72 λ 0 ×0.08 λ 0 at 6.2 GHz. The measured −10 dB impedance bandwidth of the antenna is 25.17% (5.21 GHz-6.71 GHz) and the measured 3 dB axial ratio bandwidth is 17.42% (5.87 GHz-6.99 GHz). Moreover, the highest gain in the working frequency band is 7.52 dBic. The proposed CP MS antenna has good application prospects in C-band satellite communications.

A novel dual-sense polarization reconfigurable dual-band microstrip antenna

This article presents a miniaturized reconfigurable tri-polarization metantenna with compact size of 0.58 λ 0 × 0.58 λ 0 × 0.04 λ 0 ( λ 0 is the free space wavelength referring to the antenna center frequency). Metantenna means the metasurface is directly used as the antenna radiator aperture instead of an accessory. The metantenna is formed by miniaturized windmill like units, which is evolved from square patch units based on characteristic mode analysis, and 46% size reduction is achieved. Two PIN diodes are introduced into the feeding microstrip for switching among tri-polarization. The measured −10 dB impedance bandwidths are 24.6% (3.24–4.15 GHz) and 24.1% (3.26–4.05 GHz) for circular polarization (CP) and linear polarization (LP), respectively. The measured overlapped 3 dB axial ratio (AR) bandwidth is 15% (3.4–3.95 GHz). The measured peak gains are 5.15 dBi, 5.21 dBic, and 5.25 dBic for LP, left hand (LH) CP and right hand (RH) CP, respectively. The aperture efficiency is 77.3%, 78.5%, and 79.1% for LP, LHCP, and RHCP, respectively. The measured AR beamwidth (BW) of LHCP in XZ-plane and YZ-plane is 192° and 174°, respectively, the measured ARBW of RHCP in XZ-plane and YZ-plane is 201° and 166°, respectively. The developed metantenna has the following advantages: broadband 3 dB AR bandwidth, wide ARBW > 166°, least PIN number (tri-polarization with 2 PIN), and high-aperture efficiency.

This article presents a reconfigurable antenna feeding network for circular and linear polarization diversity. The proposed cir- cuit consists of two hybrid couplers and two single pole four throw switches for four configuration modes: left-hand circular polarization, right-hand circular polarization, vertical linear polarization, and hori- zontal linear polarization. For verification, a reconfigurable antenna with the proposed feeding network is designed at 917 MHz and meas- ured for switchable circular and linear polarizations. V C 2014 Wiley Periodicals, Inc. Microwave Opt Technol Lett 56:893-896, 2014; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.28243

A novel single-feed design of a patch antenna with polarization reconfigurability is proposed in this paper. Four identical notches with parasitic elements are embedded into the design. The antenna can switch between linear polarization (LP), left hand circular polarization (LHCP) and right hand circular polarization (RHCP). The results show that the proposed antenna demonstrates an impedance bandwidth of 50 MHz (S11 <;-10 dB), and a polarization bandwidth of 44.3 MHz (axial ratio <; 3 dB). Also, the axial ratio is obtained in a broad angular range when the antenna is in LHCP and RHCP mode. The structure of the proposed antenna is simple and suitable for antenna array applications that require circular polarization and polarization diversity properties.

The integration of electric field enhancement structures (EFESs) with Rydberg atomic sensors (RASs) has garnered considerable interest due to their potential to enhance detection sensitivity in quantum measurement systems. Despite this, there is a dearth of research on the directional response of EFES, and the analysis of the three-dimensional (3D) patterns of RAS remains a formidable challenge. RASs are employed in non-destructive measurement techniques, and are responsive to electric fields, primarily serving as reception devices. However, analyzing their reception patterns is a complex task that requires a sophisticated approach. To address this, we adopt characteristic mode (CM) analysis to illustrate the omnidirectional performance of RAS. According to the CM theory, the reception pattern can be calculated by a series of modal currents and their corresponding coefficients. The analytical representation of these coefficients negates the need for time-consuming full-wave (FW) numerical simulations, which are typically required to generate EFES patterns due to the necessity of scanning numerous angle parameters. This approach significantly reduces the complexity of solving EFES patterns, and provides insightful guidance for the design process. To validate the efficacy of our proposed method, we construct three prototypes. The results indicate that the final model resonates at 1.96 GHz, achieving an electric field gain of 25 dB and an out-of-roundness of 2.4 dB. These findings underscore the effectiveness of our method in analyzing EFES patterns, highlighting its potential for future applications in the field.

본 논문은 UHF RFID 시스템을 위해 편파를 선택할 수 있는 리더 안테나를 설계 및 구현하였다. 제안된 리더 안테나는 두 개의 급전부를 가지는 마이크로 스트립 패치 안테나와 두 개의 SPDT 스위치와 하나의 SP4T 스위치와 3dB hybrid coupler로 구성되어 있다. 각각의 스위치 전압을 조절하여 수직 방향의 선형 편파와 수평 방향의 선형 편파, 좌수 원형 편파와 우수 원형 편파를 선택할 수 있다. 제안된 안테나는 902MHz~928MHz 대역에서 VSWR 2:1 기준으로 UHF RFID 주파수 대역인 902MHz~928MHz를 만족한다. 안테나의 최고이득은 X-Y Plane을 기준으로 선형 편파가 선택되어질 때 7.71dBi, 7.55dBi 로 측정되었고 원형 편파가 선택되어질 때 7.31dBic, 7.81dBic 로 측정되었다. 또한 원형 편파(LHCP, RHCP)가 선택 되어질 때 축비는 각각 2.01~2.83dB, 2.02~2.60dB로 측정되었고 이는 3dB 이하의 축비를 만족한다. TIn this paper, it is designed the polarization selective antenna for UHF RFID system. The proposed antenna is consist of microstrip patch antenna with dual feeding and two SPDT switches and a SP4T switch and 3dB hybrid coupler. Through control of voltage of switches, the proposed reader antenna can select horizontally linear polarization, vertically linear polarization, left-hand circular polarization (LHCP) and right hand circular polarization (RHCP). The proposed reader antenna satisfied 2:1 VSWR at 902MHz~928MHz. and it has under 3dB AR(axial ratio). Peak gain of antenna is 7.71dBi, 7.55dBi with linear polarization and 7.31dBic, 7.81dBic with circular polarization at x-y plane. Also Axial ratio of antenna is 2.01~2.83dB and 2.02~2.60dB respectively. It is satisfied 3dB axial ratio.

An electronically reconfigurable microstrip antenna with circular and linear polarization switching is presented. The prototype fabricated on a substrate of dielectric constant (ε <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">r</sub> ) 4.4 and height (h) 1.6 mm is fed by a proximity feed fabricated using the same substrate. By controlling the bias voltage of two PIN diodes, the polarization of the antenna can be switched between three states; two states for linear polarization (horizontal and vertical) and one state for circular polarization (RHCP). Simulation and experimental results show that the proposed antenna has a cross polar level better than 10 dB in the linear polarization state and 18 MHz axial ratio bandwidth in the circular polarization state. The frequency and polarization diversities of this design could potentially improve the reliability of wireless communication systems.

In this paper a compact dual-feed Global Positioning System (GPS) antenna for simultaneous left- and right hand circularly polarized wave reception is presented. The antenna structure consists of a single patch antenna on top of a printed circuit board and two aperture coupled feeds in the ground plane which are used to generate both left- and right-hand (LH and RH) circular polarizations for the patch. The feed network is implemented as a 2-section branch-line coupler underneath the ground plane. It is able to generate adequate phase shifts for both LH and RH circular polarizations simultaneously via two feed ports. Due to the aperture coupling and coupler implementation three layer printed circuit board approach is used. The measured axial ratio is < 1.35 for both polarizations over the 24 MHz bandwidth at the frequency of 1.575 GHz. The isolation between the LH and RH feed ports in reception mode is −35… −26 dB in the broadside direction. The antenna enables simultaneous direct and multipath signal measurement with equal spatial coordinates for both polarizations.

view Abstract Citations (21) References (42) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS Interstellar Circular Polarization and the Dielectric Nature of Dust Grains Chlewicki, Grzegorz ; Greenberg, J. Mayo Abstract The relationship between interstellar linear and circular polarization is reexamined. The derivation of optical constants for relevant materials is described, emphasizing general constraints on the electromagnetic response of an optical medium (Kramers-Kronig relations) which also provide the basis for the subsequent analysis of interstellar polarization. The formulas that relate the observed polarization to the properties of individual grains are summarized. It is shown that the apparent upper limit on the visual absorptivity of grains derived from earlier Mie theory calculations results from a violation of the Kramers-Kronig relations in the assumed optical constants of the particles. The analysis of circular and linear polarization in the interstellar medium is presented, and the implications of this analysis for grain models are addressed. Publication: The Astrophysical Journal Pub Date: December 1990 DOI: 10.1086/169474 Bibcode: 1990ApJ...365..230C Keywords: Circular Polarization; Dielectrics; Interstellar Extinction; Interstellar Matter; Optical Properties; Interstellar Gas; Linear Polarization; Mie Scattering; Astrophysics; INTERSTELLAR: GRAINS; POLARIZATION full text sources ADS |

Fully polarimetric radars are capable of preserving detailed information about the targets because of the amplitude and phase information they contain which helps in distinguishing different scattering mechanisms. Therefore, nowadays it is needed to use this information for various applications, i.e., classification, target identification etc. In polarimetry, circular (L: left-hand circular polarization and R: right-hand circular polarization) as well as linear (H: horizontal polarization and V: vertical polarization) polarizations have their own advantages. In this paper, an attempt has been made to highlight the effect and importance of both types of polarizations for land-cover classification using ALOS (Advanced Land Observing Satellite) PALSAR (Phased Array-type L-band Synthetic Aperture Radar) quad-polarimetric data. Polarization responses from certain targets in linear (i.e., HH, HV, VV) and circular (i.e., LL, LR, RR) bases have been extensively analysed. Supervised classification using minimum distance classifier is used to examine the performance of both the polarization bases for terrain classification. It has been observed that circular basis polarization may be suitable for better estimation of water class unlike linear basis polarization and inclusion of circular basis enhances the classification results. This type of study will be quite helpful in the near future to enhance the special features of terrain covers.

This article presents an innovative design for a low-profile, high-gain circularly polarized (CP) antenna using a single-layer metasurface (MTS). The proposed design incorporates an MTS layer, comprising a 4 × 4 array of hexagonal-shaped patches, printed on the top layer of the substrate. The bottom layer features a coplanar waveguide-fed slotted ground. Circular polarization and broadside radiation are achieved through the application of characteristic mode analysis (CMA). CMA is employed to simultaneously excite desired modes, aiming for wideband circular polarization and gain enhancement. Experimental results validate the effectiveness of the design, with compact dimensions of 0.67λ0 × 0.67λ0 × 0.04λ0. The measurements demonstrate an impressive impedance bandwidth of 84.3% within the 3.7–9.1 GHz. Additionally, a 3-dB axial ratio bandwidth of 18.6% is observed between 4.96 and 5.98 GHz and 3.74% between 8.38 and 8.7 GHz. The antenna exhibits excellent radiation pattern characteristics, featuring a maximum gain of 10.08 dBi at 7.1 GHz. The radiation pattern is symmetrical with broadside directionality, making the antenna well-suited for sensing applications.

Based on the temperature-controlled phase transition property of vanadium dioxide (VO2), a tunable broadband polarization converter in the terahertz band has been designed, which achieves a flexible and reversible conversion between transmission and reflection modes. Our results show that the polarization conversion of this converter can be achieved by changing the phase transition of VO2. When VO2 in the insulating state, the transmission polarization conversion (TPC) can be realized to obtain the ideal broadband linear-to-linear (LTL) polarization conversion, and the conversion efficiency is more than 0.99 in the range of 0.99–2.94 THz. When VO2 is in the metallic state, reflection polarization conversion (RPC) can be realized, achieving relatively perfect linear-to-right-hand circular polarization (LTRHCP) and linear-to-left-hand circular polarization (LTLHCP) conversions in different frequency bands. A right-hand circular polarization (RHCP) wave can be obtained from 0.8–1.87 THz, and a left-hand circular polarization (LHCP) wave can be obtained from 2.46–3.15 THz. The points of metasurface polarization converter proposed have the advantages of multi-conversion mode, multi-function, high polarization conversion efficiency, broadband, etc The working principle of the transmission and reflection polarization conversion mode is explained by surface current and electric field. In addition, the structure is insensitive to incident angle and has huge application potential in the fields of communication, imaging, sensing, etc