Prototype Of Patch Antenna Research Articles

Design and simulation of a novel THz patch antenna for early detection of malignant neoplasms

This research presents a novel patch antenna prototype that operates in the THz range for early detection of malignant cancerous cells. The antenna has dimensions of 100 µm × 100 µm and achieves −27.3 dB return loss at an operating frequency of 2.34 THz. The proposed sensor is optimized for a polyimide substrate with a dielectric constant of 3.5 and thickness of 15.7 µm. The prototype’s sensitivity and performance are evaluated by simulating different malignant neoplasms using High-Frequency Simulation Software (HFSS) for five types of breast cancer cells. The results indicate that the variation in resonant frequency and the S21 parameter between malignant cells and healthy breast cells are the primary factors that determine the sensitivity of the prototype. The proposed patch antenna’s high sensitivity and low profile make it a promising solution for the early detection and prognosis of cancerous cells.

A novel modified circular ring-based broadband polarization-insensitive angular stable circuit analog absorber (CAA) for RCS applications

AbstractIn this study, a compact modified circular ring-based circuit analog absorber (CAA) is proposed. It comprises a resistor-loaded frequency selective surface (FSS) underneath an FR-4 substrate, and the other end is terminated with a perfect electric conductor (PEC) separated by an air-spacer. The proposed design shows a minimum −10 dB reflectance from 10.55 to 36.03 GHz (25.48 GHz bandwidth and 109.4% fractional bandwidth) with two dips at 13.5 GHz and 35.23 GHz having reflectivity −17.18 dB and −24.9 dB, respectively. The existing four-fold circular symmetry architecture shows insensitivity for different polarization angles under normal incidences and up to 45° stability for Transverse Electric (TE) and Transverse Magnetic (TM) modes under oblique incidences. The proposed cell is compact with a periodicity of 0.193λL, and a thickness of 0.09λL, where λL is the free-space wavelength corresponding to the lowest frequency of the absorption band. The novelty of the design lies in the topology of using an underneath FSS to take advantage of effective permittivity control for both broader bandwidth and better angular stability. To demonstrate the ability of the proposed design, a 28 GHz microstrip patch antenna prototype is fabricated, and its radar cross section (RCS) is measured after loading with the absorber. A 15.15 dBsm RCS reduction is observed in comparison with the PEC. The authors strongly believe that the proposed design has potential applications such as RCS reduction and radio-frequency energy harvesting.

Design of low-cost microstrip patch antennas with robust optimization

ABSTRACT This paper presents a robust optimization method to design patch antennas that consider uncertainties from the substrate electromagnetic properties and the manufacturing equipment. The robust optimization method is proposed to design an antenna that uses FR-4 as a substrate, addressing the uncertainties originated from the lack of standardization of this material properties and errors in the manufacturing process of the antenna. By addressing these uncertainties, robust design can result in a low-cost antenna with good performance that is less sensitive to deviations in the defined project variables. The optimization scheme used in this paper is based on NSGA-II, and the robustness of its solutions is quantified with the standard deviation of samples from the performance parameters in the uncertainty set from the design parameters. Two prototypes of patch antennas, one with linear and the other with circular polarization are designed, built, and measured.

Triband Circularly Polarized Antenna Using a Single Patch

A single-feed single-patch triband antenna with different senses of circular polarization in different operating bands is presented in this letter. The first three pairs of the orthogonal modes of a single patch, TM10/TM01, TM20/TM02, and TM30/TM03 modes, are excited to serve the triband circularly polarized operation, by loading stubs and etching slots in both x - and y - directions. Benefited from the asymmetrical radiating patch and aperture coupling on the diagonal line, the orthogonal modes can be well excited and controlled to realize the different senses of circular polarization in different operation bands by tuning the stubs and slots. A patch antenna prototype has been designed and fabricated for experimental validation. The measured 3 dB axial ratios (ARs) of the three bands are 2.439–2.452 GHz, 3.343–3.365 GHz, and 4.342–4.378 GHz, respectively, and the corresponding polarizations are left-hand circularly polarized (LHCP), right-hand circularly polarized (RHCP), and RHCP, respectively.

Miniaturized broadband‐multiband planar antenna with a symmetric quarter‐circular ground plane for WLAN/WiMAX standards

AbstractIn this paper, a novel design of miniature and broadband‐multiband coplanar waveguide‐fed planar antenna with a symmetric quarter‐circular ground plane is suggested to realize multiband with better performance. The experimental results show that the suggested antenna has achieved two bandwidths (S11 < −10 dB): the lower band from 2.34 to 2.42 GHz centered around the resonant frequency of 2.38 GHz and the upper broadband from 3.16 to 6.57 GHz resonating at 3.5 and 5.38 GHz, respectively. The bandwidths cover the two required bands: WiMAX and WLAN at the frequencies 3.5/5.5 and 2.4/5.2/5.8 GHz, respectively. All these three resonant frequencies show better impedance matching with convenient gain and high radiation efficiency; moreover, the radiation patterns in the H‐plane and E‐plane are omnidirectional and bidirectional, respectively. The patch antenna prototype is constructed on a simple substrate named FR4 epoxy and having total dimensions of 0.23λ × 0.14λ × 0.012λ, as λ is the free‐space wavelength at the lower resonant frequency. In addition, the resulting multiband antenna is a highly compact size and having a good performance, which makes it appropriate for wireless systems in diverse applications.

A Feeding Technique for Wideband CP Patch Antenna Based on 90° Phase Difference Between Tapped Line and Parallel Coupled Line

A feeding technique for wideband circularly polarized (CP) patch antenna based on the 90° phase difference between tapped line and parallel coupled line in a feeding network is proposed. The tapped line and parallel coupled line are equivalently regarded as a direct coupling element with 0° phase delay and a J -inverter coupling element with 90° phase delay, respectively. In design, two identical λ /2 resonators are employed to excite two orthogonal modes for wideband equal magnitude. Meanwhile, the feeding lines are tapped and coupled to the two resonators, and tapped line and coupled line can inherently provide 90° phase difference as demanded for CP radiation with no need for an additional delay line or a phase shifter. The whole structure is modeled as an equivalent three-port network, and the theoretical axial ratio (AR) is calculated with the magnitude and phase of the voltage at the radiation conductance. Since two minima in AR response emerge, this proposed patch antenna can achieve a wide AR bandwidth. The theoretical performance is finally verified by a fabricated CP patch antenna prototype with a profile of 0.042 λ 0, and the 3 dB AR fractional bandwidth is 7.07%.

A Low-Profile Antenna With Omnidirectional and Unidirectional Radiation Patterns Over Two Operation Bands

A compact low-profile dual-band antenna with a single circular radiation patch is presented. The circular radiation patch is top-loaded by a metal strip, leading to a zeroth-order resonant (ZOR) mode with monopole-like radiation pattern at the lower operation band, and the ZOR mode is not affected by the position change of the probe feed. Thereby an off-center probe feed can be used to excite a TM01 mode with patch-like radiation pattern at the upper operation band, and its performance remains good stability when the size of the metal strip is varying. The equivalent circuit, electric field and current distributions of the proposed antenna are studied to investigate the principles of the ZOR and the TM01 modes, and all the results show that the two operation bands can be effectively and independently controlled. As a proof-of-concept, a circular patch antenna prototype with low profile of about $0.023~\lambda _{0}$ at 2.35 GHz is fabricated and tested. Good agreements between the measured and simulated results are achieved, showing monopole-like and patch-like radiation patterns within 2.28 - 2.40 GHz and 3.30 - 3.60 GHz, respectively, and the average realized gains are about 2.5 dBi and 8.5 dBi for the two operation bands.

Wideband Patch Antenna With Ground Radiation Mode and Patch Radiation Mode

In this paper, patch antenna structures are studied to simultaneously excite the ground radiation mode and patch radiation mode. Based on the analysis of characteristic current distribution on the ground plane of patch antenna, an exciting method of the ground radiation mode is proposed. Then a dual-mode patch antenna of patch radiation and ground radiation is designed, which can achieve a wideband radiation using two modes resonating at two adjacent frequencies. To improve the radiation efficiency of the ground mode, the electric field distribution of the dual-mode antenna is investigated in detail and the electric field models for two modes are constructed. It is suggested that the additional notches introduced on the ground plane can enhance the resonance component of the ground mode. By this way, the modified patch antenna presents better radiation efficiency over the operating band. The measurement results show that the relative bandwidth of the patch antenna prototype with the notches is about 16.2%, defined by the reflection coefficient less than -10 dB. The proposed dual-mode antennas have the inherent characteristics of weak directivity, for that the antenna application scenarios also are indicated.

Co-Design of a Wideband Circularly Polarized Filtering Patch Antenna With Three Minima in Axial Ratio Response

A co-design of a wideband circularly polarized (CP) patch antenna is proposed in this paper. The patch antenna is seamlessly integrated with two bandpass filter networks consisting of one and two $\lambda $ /2 resonators, respectively, which are designed to excite two orthogonal modes with equal magnitude and quadrature phase over a widened bandwidth. In co-design of this filtering antenna, the patch antenna is equivalently treated as the last-stage resonator and the output port of the filter network. In analysis of its far field, axial ratio (AR) of CP wave is mapped to its magnitude and phase responses. By simultaneously synthesizing the magnitude ratio and phase difference of the two filter networks’ transmission coefficients to vary around 1° and 90°, respectively, wideband AR response with three minima is realized. Based on this design method and the theoretically derived results, a CP patch antenna prototype with a height of $0.028\lambda _{0}$ is fabricated and measured. It is experimentally demonstrated that around 8.8%, bandwidth can be achieved with VSWR < 2, AR < 3 dB, and 3 dB gain variation.

Square Ring Antenna With Reconfigurable Patch Using Shape Memory Alloy Actuation

A pattern reconfigurable ring-patch antenna is presented. It comprises a bendable parasitic plate located in the middle of a fixed square ring. The fixed ring supports the feed, and the plate is effectively a parasitic structure. The plate's bending action is from a bisecting hinge between the rectangular halves (flaps) that can be actuated separately. The actuation is by extending a shape memory alloy spring. The restoration is by decompressing the shape memory spring action using a parallel standard spring. The parasitic plate thus reconfigures with rectangular flaps which bend up, level, and down, relative to the ring plane. As a result of the reconfiguration, the pattern of the antenna is changed while the impedance match is maintained. Simulated and experimental results are presented for the pattern and impedance of a 100 mm × 100 mm square ring patch antenna prototype operating at 1.15 GHz. The effects of some geometric parameters on the pattern and impedance are investigated in order to analyze the pattern changing mechanism. A two-element array of the reconfigurable ring-patch antenna is presented that provides further de-correlation of the patterns.