Design Of Circularly Polarized Antenna Research Articles

Implantable small ultra-wideband circularly polarized antenna design for continuous blood pressure monitoring

This paper presents a miniaturized circularly polarized (CP) implantable antenna Ultra-wide bandwidth for continuous blood pressure monitoring. The miniature and CP of the antenna are gained by using a new slot method. The symmetry slots in the radiation patch, two T-shape slots in the GND, coupled with the use of a short pin make the designed antenna with good physical and radiation properties. In simulation, the fractional effective axial ratio bandwidth is 23.6% (2.36–2.94 GHz), and the peak gain is − 28.9 dBi. Its total size is only 17.78 mm3 (0.056 × 0.04 × 0.004 λ03), which size is smaller compared to other antennas with similar performance. A prototype is fabricated and measured. The experimental results are in good agreement with the simulation results. And, the radiation patterns have good symmetry both in the simulation and measurement. In addition, the maximum SAR value is in accordance with the IEEE standard safety guidelines (IEEE C95.1-2019).

EZR-MZR Resonators for Compact Low-Profile Omnidirectional Circular-Polarized Antenna Design

New zeroth-order resonator (ZOR): the curved EZR-MZR resonator [epsilon-zero resonance (EZR) and mu-zero resonance (MZR)] was proposed for circular-polarized (CP) antenna design with low-profile and omnidirectional characteristics. The proposed curved EZR-MZR resonator has two orthogonal polarizations with 90° phase difference (PD). By forming four resonators in a circular ring array, the MZR can be characterized as a magnetic dipole. Then, the unidirectional pattern of the horizontal polarization was transformed to be omnidirectional while the EZR with vertical polarization can be characterized as an electric dipole and it radiates omnidirectional pattern. As the PD of the vertical and the horizontal polarizations is inherently 90°, the allying of the two orthogonal polarizations leads to a CP radiation with an omnidirectional pattern. To feed the resonators with uniform amplitude and phase, a feeding network with four equal radial arms is used. The proposed omnidirectional CP antenna has the advantages of low profile from ZOR characteristics and high design efficiency from the inherent 90° PD between the orthogonal polarizations. A prototype with resonant frequency of 1.544 GHz was designed with a diameter of 57 mm (0.29 $\lambda _{r}$ , $\lambda _{r}$ is the free space wavelength of the resonant frequency) and a height of 4 mm (0.02 $\lambda _{r}$ ).

Compact Design of Circularly Polarized Antenna with Vertical Slotted Ground for RFID Reader Application

A novel compact circular polarization (CP) microstrip antenna is proposed for UHF ultrahigh frequency (UHF) radio frequency identification (RFID) reader applications. The proposed antenna is composed of a corner truncated square-ring radiating patch on a substrate and a vertical slotted ground surrounding four sides of the antenna. A new feeding scheme is designed from flexible impedance matching techniques. The impedance bandwidths for S11<-10 dB and 3 dB axial ratio (AR) bandwidth are 12.1% (794.5–896.5 MHz) and 2.5% (833.5–854.5 MHz), respectively.

Compact Dual-Band Circularly Polarized Antenna Design for Navigation Terminals

A dual-band circularly polarized antenna with advantages of agile frequency configuration, compact size, and light weight is proposed in this letter. The antenna size can be reduced by employing a rectangular ring radiator structure. Simultaneously, the operating frequency of the proposed antenna can be readily tuned by properly stacking the ring radiators with tunable dimensions. To verify the accuracy and robustness of the proposed design, antennas with different frequency ratios are designed. Both simulated and measured results are presented to verify the proposed design.

Single‐feed cross‐slot loaded compact circularly polarized microstrip antenna for indoor WLAN applications

ABSTRACTA novel single‐feed circularly polarized microstrip antenna with compact size is proposed for indoor wireless local area network (WLAN) applications. The antenna structure consists of eight slits which are introduced at the boundary and the corners in the radiating square patch with a cross‐slot at the center. The proposed antenna shows a compactness of 42% compared with the conventional circularly polarized antenna design at indoor WLAN frequency band. It is found that the resonance frequency of the proposed structure is highly depending on length and width of cross‐slot and corner slit for entire band of circular polarization. The 3 dB axial ratio bandwidth of the proposed antenna is 1.9%. Proposed structure is fabricated on the FR‐4 epoxy substrate and fed by a single coaxial probe. Measured results show a good agreement with the simulated results. Antenna shows stable radiation characteristics for the entire operating band. © 2014 Wiley Periodicals, Inc. Microwave Opt Technol Lett 56:1313–1317, 2014

A Compact Circularly Polarized Antenna Using an Array of Folded-Shorted Patches

The development and optimization of a circularly polarized (CP) antenna using an array of four folded-shorted patch elements is investigated. The realized antenna is compact ( 0.2λ0 by 0.2λ0), highly integrated, and offers good radiation performance at 400 MHz. A compact coupler-based feeding network for the four elements within the array, integrated into the antenna ground plane, provides a sequential 90° phase difference between the radiating folded-shorted patches. This very compact CP antenna design may be useful for microsatellite and other miniaturized phased array systems for communications.

DESIGN OF DUAL CIRCULARLY POLARIZED ANTENNA WITH HIGH ISOLATION FOR RFID APPLICATION

In this paper, a dual-fed circularly polarized antenna design with high isolation is presented for radio frequency identiflcation (RFID) reader. The proposed antenna is excited by two fed ports connected with a circular split-ring microstrip line underneath the ground plane. A radial aperture in the ground plane provides coupling between the split-ring microstrip and radiating patch. For multiple RFID band requirements, the dimension of the aperture can be modifled to obtain high isolation on difierent RFID Band. Finally, an antenna prototype for China RFID Band (920{925MHz) is fabricated. The measured results agree well with simulation, and show 10-dB matching bandwidth of 18% (820{1000MHz), 3-dB axial ratio (AR) bandwidth of 11% (854{960MHz), and 25-dB isolation bandwidth of 11MHz (917{928MHz).

Research on the L-band circularly polarized antenna with low RCS level

A novel L-band circularly polarized (CP) microstrip antenna for low radar cross-section (RCS) application is proposed in this paper. A corner-cut squarer radiator is used to implement the CP radiation. The antenna RCS is effectively reduced by the special quasi-fractal structure on the ground plane. Its radiation and scattering performances are simulated and experimentally verified by being compared with those of a commonly used CP microstrip antenna which is chosen as a reference antenna. The results show that the proposed antenna has good radiation performances and lower RCS than the reference antenna. The proposed antenna serves as a good candidate in the design of CP antenna with the requirement of low RCS.

Tri-band circularly polarized annular slot antenna for GPS and CNSS applications

A novel single-feed tri-band circularly polarized (CP) annular slot antenna is presented. The antenna structure is composed of two nonconcentric annular slots that are fed by an L-shaped series step impedance microstrip line configuration. The proposed antenna is designed to operate at the L 1 and L 2 bands of the global positioning system and the operating band of the compass navigation satellite system. Compared to the most of the previously reported tri-band CP antenna structure, the proposed antenna has low profile, compact size, and easy fabrication on the single-layer PCB. The measured results show that the impedance bandwidths are good for all bands. The axial ratio bandwidth and radiation patterns are also measured at the three resonant frequencies. The proposed compact tri-band CP antenna design is suitable for mounting onto the mobile communication devices and portable positioning systems.

A single-feed tri-band circularly polarized dual-annular slot antenna for wireless applications

A novel single-feed tri-band circularly polarized (CP) dual-annular slot antenna is presented. The antenna structure is composed of two nonconcentric annular slots fed by a novel inverted h-shaped microstrip line configuration. Compared to most of the previously reported tri-band CP antenna structures, the proposed antenna has low profile, compact in size, and easy to fabricate on the single-layer PCB. It is easy for the antenna to match all the three frequency bands by employing an h-shaped feeding line. The antenna also can provide a conical radiation pattern at the third band. A sample design of a tri-band CP antenna operated at 1.58, 2.42, and 3.0 GHz is realized. Details of the experimental results compared with simulated results are presented and discussed. The proposed compact tri-band CP antenna design is suitable for mounting onto the mobile communication devices and portable positioning systems.

Planar Wideband Circularly Polarized Antenna Design With Rectangular Ring Dielectric Resonator and Parasitic Printed Loops

A wideband circularly polarized (CP) rectangular dielectric resonator (DR) parasitically coupled to a printed rectangular loops is presented. The DR is housed in a thin dielectric substrate with a microstrip line and narrow strip printed from one side and a ground plane and conducting loops and lines connected to the ground plane. The DR is linearly polarized, and for CP, we introduced printed conducting loops in the other side of the DR, which produce the orthogonal polarization with the required quadratic phase. Several loops are used to achieve the wide CP band. The final design achieves CP with 51% bandwidth. The reflection coefficient, axial ratio (AR), radiation patterns, gain, and efficiency of the antenna are studied, and reasonable agreement between the measured and simulated results is observed.

Design of CP Antenna with a Fenced Ground for a Handheld RFID Reader

A design of circular polarized(CP) microstrip antenna with a fenced ground is proposed and the equivalent circuit is derived. The antenna consists of a square radiating patch with a pair of truncated corners, a bottom ground and a fenced ground. From conducted experiments, a patch size reduction using the metal fence as large as 25 % from the conventional patch structure, has been obtained. The input admittance of the extracted equivalent circuit is shown to agree with that of the measurement. And the design parameters and performance of the proposed antenna are examined by analyzing the fields and circuit behaviors.