Design and implementation of low profile antenna for dual-band applications using rotated e-shaped conductor-backed plane.
Ontology highlight
ABSTRACT:
SUBMITTER: Jalali M
PROVIDER: S-EPMC3953436 | biostudies-other | 2014
REPOSITORIES: biostudies-other
Similar Datasets
Project description:A novel probe-fed compact inverted S-shaped multifrequency patch antenna is designed. By employing two rectangular slots that change the conventional rectangular patch into an inverted S-shaped patch, the antenna is able to operate in triple frequency in the X-band. The performance criteria of the proposed design have been experimentally verified by fabricating a printed prototype. The measured results show that the -10 dB impedance bandwidth of the proposed antenna at lower band is 5.02% (8.69-9.14 GHz), at middle band is 9.13% (10.47-11.48 GHz), and at upper band is 3.79% (11.53-11.98 GHz). Two elliptical slots are introduced in the ground plane to increase the peak gain. The antenna is excited by a simple probe feeding mechanism. The overall antenna dimension is 0.52λ × 0.60λ × 0.046λ at a lower resonance frequency of 9.08 GHz. The antenna configuration and parametric investigation are conducted with the help of the high frequency structural simulator, and a good agreement is achieved between the simulated and measured data. The stable gain, omnidirectional radiation pattern, and consistent radiation efficiency in the achieved operating band make the proposed antenna a suitable candidate for X-band applications.
| S-EPMC4033478 | biostudies-other
Project description:A wearable C-shaped antenna based on a fabric material operating at 2.4 GHz frequency is proposed for use in flexible/wearable IoT medical systems. The wearable IoT device plays a key role in medical applications, and the antenna is a key part of it. Loading the presented antenna on the body models showed a frequency detuned with the gain and efficiency reduced from 1. 28 to −9 dB and 90% to 10%. In addition, the SAR did not meet the safety health requirement defined by the FCC or ICNIRP standards. Therefore, an “Artificial Magnetic Conductor” structure (AMC) is added to the C-shaped antenna to overcome these problems. The AMC acts as shielding material between the human skin and the presented antenna because of its 0° reflection phase, which mimics the action of the Perfect Magnetic Conductor (PMC). The overall size of the proposed design was 54 × 54 × 3.9 mm3. Numerical and experimental findings indicated that integrating the AMC structures with a C-shaped antenna was robust for body deformation and load. The C-shaped antenna worked equally well with the AMC, whether positioned in free space or on the chest or the arm of the human body. The integrated antenna with AMC structures has excellent performances. The gain and efficiency without loading on the chest were 6.49 dB and 84%, respectively. While for loaded on the chest were 6.21 dB and 81%, respectively. It also decreased the back radiation and raised the Front to Back Ration (FBR) by 13.8 dB. SAR levels have been reduced by more than 90% between the FCC and ICNIRP standards compared to the C-shaped antenna alone, which does not comply with the standards. As a result, the C-shaped integration with AMC structures is highly suitable for assembly in any wearable system. Supplementary Information The online version contains supplementary material available at 10.1007/s11276-021-02770-4.
| S-EPMC8435302 | biostudies-literature
Project description:This paper reports a two-orders-of-magnitude improvement in the sensitivity of antenna-coupled nanothermocouple (ACNTC) infrared detectors. The electrical signal generated by on-chip ACNTCs results from the temperature difference between a resonant antenna locally heated by infrared radiation and the substrate. A cavity etched under the antenna provides two benefits. It eliminates the undesirable cooling of the hot junction by thermally isolating the antenna from the substrate. More importantly, careful cavity design results in constructive interference of the incident radiation reflected back to the antenna, which significantly increases the detector sensitivity. We present the cavity-depth-dependent response of ACNTCs with cavity depths between 1 μm and 22 μm. When constructive interference is maximized, the thermal response increases by 100-fold compared to devices without the cavity.
| S-EPMC6610083 | biostudies-literature
Project description:In this paper, a novel dual band frequency reconfigurable antenna using an origami magic cube is proposed for wireless sensor network (WSN) applications. The proposed origami antenna consists of a meandered monopole folded onto three sides of the magic cube. A microstrip open-ended stub is loaded on the meandered monopole. The proposed origami magic cube can be mechanically folded and unfolded. The proposed antenna operates at 1.57 GHZ and 2.4 GHz in the folded state. In the unfolded state, the proposed antenna operates at 900 MHz and 2.3 GHz. The resonant frequency of the second band can be tunable by varying the length and position of the open stub. The origami magic cube is built on paper. Its performance is numerically and experimentally demonstrated from S-parameters and radiation patterns. The measured 10 dB impedance bandwidth of the proposed origami antenna is 18% (900-1120 MHz) and 15% (2.1-2.45 GHz) for the unfolded state and 20% (1.3-1.6 GHz) and 14% (2.3-2.5 GHz) for the folded state. The measured peak gain at 900 MHz and 2.3 GHz are 1.1 dBi and 2.32 dBi, respectively, in the unfolded state. The measured peak gain at 1.5 GHz and 2.4 GHz are 3.28 dBi and 1.98 dBi, respectively, in the folded state.
| S-EPMC5712905 | biostudies-literature
Project description:This paper introduces a new configuration of compact, triangular- and diamond-slotted, microstrip-fed, low-profile antenna for C/X band applications on polytetrafluoroethylene glass microfiber reinforced material substrate. The antenna is composed of a rectangular-shaped patch containing eight triangles and two diamond-shaped slots and an elliptical-slotted ground plane. The rectangular-shaped patch is obtained by cutting two diamond slots in the middle of the rectangular patch, six triangular slots on the left and right side of the patch, and two triangular slots on the up and down side of the patch. The slotted radiating patch, the elliptical-slotted ground plane, and the microstrip feed enable the matching bandwidth to be widened. A prototype of the optimized antenna was fabricated on polytetrafluoroethylene glass microfiber reinforced material substrate using LPKF prototyping machine and investigated to validate the proposed design. The simulated results are compared with the measured data, and good agreement is achieved. The proposed antenna offers fractional bandwidths of 13.69% (7.78-8.91 GHz) and 10.35% (9.16-10.19 GHz) where S11 < -10 dB at center frequencies of 8.25 GHz and 9.95 GHz, respectively, and relatively stable gain, good radiation efficiency, and omnidirectional radiation patterns in the matching band.
| S-EPMC4058806 | biostudies-other
Project description:Infrared nano-spectroscopy based on scattering-type scanning near-field optical microscopy (s-SNOM) is commonly employed to probe the vibrational fingerprints of materials at the nanometer length scale. However, due to the elongated and axisymmetric tip shank, s-SNOM is less sensitive to the in-plane sample anisotropy in general. In this article, we report an easy-to-implement method to probe the in-plane dielectric responses of materials with the assistance of a metallic disk micro-antenna. As a proof-of-concept demonstration, we investigate here the in-plane phonon responses of two prototypical samples, i.e. in (100) sapphire and x-cut lithium niobate (LiNbO3). In particular, the sapphire in-plane vibrations between 350 cm-1 to 800 cm-1 that correspond to LO phonon modes along the crystal b- and c-axis are determined with a spatial resolution of < λ/10, without needing any fitting parameters. In LiNbO3, we identify the in-plane orientation of its optical axis via the phonon modes, demonstrating that our method can be applied without prior knowledge of the crystal orientation. Our method can be elegantly adapted to retrieve the in-plane anisotropic response of a broad range of materials, i.e. subwavelength microcrystals, van-der-Waals materials, or topological insulators.
| S-EPMC8113487 | biostudies-literature
Project description:This paper presents the design and analysis of a novel split-H-shaped metamaterial unit cell structure that is applicable in a multi-band frequency range and that exhibits negative permeability and permittivity in those frequency bands. In the basic design, the separate split-square resonators are joined by a metal link to form an H-shaped unit structure. Moreover, an analysis and a comparison of the 1 × 1 array and 2 × 2 array structures and the 1 × 1 and 2 × 2 unit cell configurations were performed. All of these configurations demonstrate multi-band operating frequencies (S-band, C-band, X-band and Ku-band) with double-negative characteristics. The equivalent circuit model and measured result for each unit cell are presented to validate the resonant behavior. The commercially available finite-difference time-domain (FDTD)-based simulation software, Computer Simulation Technology (CST) Microwave Studio, was used to obtain the reflection and transmission parameters of each unit cell. This is a novel and promising design in the electromagnetic paradigm for its simplicity, scalability, double-negative characteristics and multi-band operation.
| S-EPMC5455826 | biostudies-other
Project description:Electron Nuclear DOuble Resonance (ENDOR) is based on the measurement of nuclear transition frequencies through detection of changes in the polarization of electron transitions. In Davies ENDOR, the initial polarization is generated by a selective microwave inversion pulse. The rectangular inversion pulses typically used are characterized by a relatively low selectivity, with full inversion achieved only for a limited number of spin packets with small resonance offsets. With the introduction of pulse shaping to EPR, the rectangular inversion pulses can be replaced with shaped pulses with increased selectivity. Band-selective inversion pulses are characterized by almost rectangular inversion profiles, leading to full inversion for spin packets with resonance offsets within the pulse excitation bandwidth and leaving spin packets outside the excitation bandwidth largely unaffected. Here, we explore the consequences of using different band-selective amplitude-modulated pulses designed for NMR as the inversion pulse in ENDOR. We find an increased sensitivity for small hyperfine couplings compared to rectangular pulses of the same bandwidth. In echo-detected Davies-type ENDOR, finite Fourier series inversion pulses combine the advantages of increased absolute ENDOR sensitivity of short rectangular inversion pulses and increased sensitivity for small hyperfine couplings of long rectangular inversion pulses. The use of pulses with an almost rectangular frequency-domain profile also allows for increased control of the hyperfine contrast selectivity. At X-band, acquisition of echo transients as a function of radiofrequency and appropriate selection of integration windows during data processing allows efficient separation of contributions from weakly and strongly coupled nuclei in overlapping ENDOR spectra within a single experiment.
| S-EPMC5376364 | biostudies-literature
Project description:This paper presents the design and realization of a compact ultra-wideband (UWB) antenna with a rectangular notch wireless area network (WLAN) band that has controllable notched bandwidth and center frequency. The UWB characteristics of the antenna are achieved by truncating the lower ends of the rectangular microstrip patch, and the notch characteristics are obtained by using electromagnetic bandgap (EBG) structures. EBGs consist of two rectangular metallic conductors loaded on the back of the radiator, which is connected to the patch by shorting pins. A rectangular notch at the WLAN band with high selectivity is realized by tuning the individual resonant frequencies of the EBGs and merging them. Furthermore, the results show that the bandwidth and frequency of the rectangular notch band could be controlled according to the on-demand rejection band applications. In the demonstration, the rectangular notch band was shifted to X-band satellite communication by tuning the EBG parameters. The simulated and measured results show that the proposed antenna has an operational bandwidth from 3.1-12.5 GHz for |S11| < -10 with a rectangular notch band from 5-6 GHz, thus rejecting WLAN band signals. The antenna also has additional advantages: the overall size of the compact antenna is 16 × 25 × 1.52 mm3 and it has stable gain and radiation patterns.
| S-EPMC7038389 | biostudies-literature
Project description:While terahertz communications are considered to be the future solutions for the increasing demands on bandwidth, terahertz equivalents of radio frequency front-end components have not been realized. It remains challenging to achieve wideband, low profile antenna arrays with highly directive beams of radiation. Here, based on the complementary antenna approach, a wideband 2 × 2 cavity-backed slot antenna array with a corrugated surface is proposed. The approach is based on a unidirectional antenna with a cardiac radiation pattern and stable frequency characteristics that is achieved by integrating a series-resonant electric dipole with a parallel-resonant magnetic dipole. In this design, the slots work as magnetic dipoles while the corrugated surface radiates as an array of electric dipoles. The proposed antenna is realized at 1 THz operating frequency by stacking multiple metallized layers using the microfabrication technology. S-parameter measurements of this terahertz low-profile metallic antenna array demonstrate high efficiency at terahertz frequencies. Fractional bandwidth and gain are measured to be 26% and 14 dBi which are consistent with the simulated results. The proposed antenna can be used as the building block for larger antenna arrays with more directive beams, paving the way to develop high gain low-profile antennas for future communication needs.
| S-EPMC5430892 | biostudies-literature