Broadband Gain Research Articles

Broadband and high gain coupled and cascaded square ring antenna for RADAR applications

Gain and bandwidth are the two primary performance characteristics of an antenna that dictate its role and utilization. In this paper, the design and fabrication details of a coupled and cascaded square ring antenna for S-band (2–4 GHz) radar communications such as navigation applications are presented. The design is employed by two square coupled rings for bandwidth enhancement and two in-phase cascaded square rings for enrichment in gain. The fabricated antenna has delivered 33% (2.52–3.52 GHz) of 10-dB bandwidth and 11.2–13.1 dBi of broadside gain. The in-phase cascading ring technique improved the antenna's gain without increasing reflector size and ring height. Thus, the proposed design is compact, with a height of 0.2λ and a total planar area of 2λ2. Moreover, the performance of the antenna is presented for variations in the geometrical parameters also.

Design and analysis of split ring resonator engraved metamaterial broadband and high gain patch antenna for THz applications

We propose a new split ring resonator engraved metamaterial MIMO patch antenna design which applies in 6–11 THz frequency band. Four different THz antennas are investigated and their results are compared to find the optimized antenna design with superstrate. The four antenna designs evolved by adding superstrate layers and metamaterials in the form of complementary split ring resonators are investigated. They are THz patch antenna (TPA), THz complementary split ring resonator patch antenna (TCPA), THz patch antenna with complementary split ring resonator superstrate (TPACS), and THz complementary split ring resonator patch antenna with complementary split ring resonator superstrate (TCPACS). The results show that the complementary split ring resonator metamaterial added in the patch as well as in the superstrate affects the antenna gain and bandwidth while the addition of the superstrate affects the multiband and gain characteristics. All four designs are optimized and show the multiband response. The TCPACS design exhibits the highest bandwidth of 900 GHz 8.88%) and the highest gain of 9.19 dB. The TCPA design is having highest bandwidth of 530 GHz (5.3%) and the highest gain of 8.05 dB. The TPACS design is having highest bandwidth of 300 GHz (3%) and the highest gain of 7.47 dB. The TPA design is having highest bandwidth of 60 GHz (0.6%) and the highest gain of 6.42 dB. The proposed antenna design with multiband, broadband, high-gain and optically transparent characteristics can be used in Terahertz Wireless Area Networks, Terahertz Wi-Fi, 6 G, Internet of Things, Sensing and Imaging applications. Availability of data and materialsThe data supporting the findings in this work are available from the corresponding author with a reasonable request.

Broadband and high gain circularly polarized mushroom‐loaded nonuniform patch array antenna with aperture CPW feed

AbstractThe circularly polarized antenna with high gain and broad bandwidth in single layer substrate is realized with mushroom‐loaded nonuniform square patches and aperture CPW feed for 5 GHz Wi‐Fi applications. An array of nonuniform square patches are excited by using a uniform aperture CPW feed. Moreover, the mushrooms are connected between the patches and the ground plane to reduce the spurious radiations on the patch. Mushrooms are moved in the diagonal direction of patches to generate circular polarization. The dimensions of the middle patches are increased and the mushrooms of the middle patches are moved further in the diagonal direction to enhance the impedance bandwidth (IBW) and 3 dB axial ratio bandwidth (ARBW). An array of mushroom‐loaded nonuniform square patches with aperture CPW feed has achieved an IBW of 54.2% (4.76–8.3 GHz), an ARBW of 14.3% (5.49–6.29 GHz) and the peak gain of 9.5–9.9 dBi over 5 GHz Wi‐Fi band.

Purely nonlinear amplified ultralow-noise transmission using hybrid second-order DRA and PPLN-based PSA.

We report ultralow-noise transmission over a 102-km single-mode fiber using a purely nonlinear amplification scheme consisting of a second-order distributed Raman amplifier (DRA) and a phase-sensitive amplifier (PSA) based on periodically poled LiNbO3 waveguides. The hybrid DRA/PSA features a broadband gain over the C and L bands and an ultralow-noise advantage, with a less than -6.3 dB effective noise figure in the DRA stage and a 1.6 dB optical signal-to-noise ratio (OSNR) improvement in the PSA stage. Compared with the unamplified link, the OSNR is improved by 10.2 dB for a 20-Gbaud 16QAM signal in the C band, resulting in error-free detection (a bit-error rate of less than 3.8 × 10-3) for the signal with a low link input power of -25 dBm. Mitigation of nonlinear distortion is also achieved by the proposed nonlinear amplified system due to the subsequent PSA.

A CMOS transimpedance amplifier with broad-band and high gain based on negative Miller capacitance

A CMOS transimpedance amplifier (TIA) with broad band and high gain based on negative Miller capacitance and capacitive degeneration has been proposed and designed. The theoretical analysis shows that by introducing negative Miller capacitance into the feedforward common gate (FCG) amplifier circuit, the bandwidth limitation caused by the internal parasitic capacitance can be reduced, and by cascading the capacitive degeneration-based common source (CS) amplifier as the gain stage, the amplifier gain can be improved simultaneously. The proposed TIA is designed and simulated in TSMC 65 nm CMOS process, The simulation results show that the −3 dB bandwidth of the amplifier circuit is 23.7 GHz, the transimpedance gain is 60.1 dBΩ, the average equivalent input noise current spectral density is less than 40.7 pA/√Hz, the power consumption is 4.8 mW, and the circuit layout area is 0.0027 mm2. In Comparison to the published TIA circuits, the bandwidth of the designed CMOS TIA is increased by 12.7 GHz, the gain is increased by 18.1 dBΩ and the circuit layout area becomes smaller. All the results demonstrate that the designed TIA can be used in the photoelectric detection circuit with broader bandwidth and higher gain.

On the resilience of dual-waveguide parametric amplifiers to pump power and phase fluctuations

Parametric amplifiers based on coupled-core fibers and coupled integrated waveguides are promising devices for delivering broadband and flat gain spectrum with low noise figure in vital technological applications such as optical communications. To address potential practical issues that may arise in the experimental demonstration, in the present work, we derive analytical expressions for the impact of relative input pump phase and power fluctuations between two waveguides on pump waves stability. We, furthermore, evaluate, through numerical simulations, how the pump power oscillations between the two waveguides affect the amplifier spectrum, identifying optimal regimes of operation for coupled-core fibers and also for coupled integrated waveguides. Our findings hint at the resilience of these parametric amplifiers' architectures and at their possible practical implementation in realistic labs and real-world scenarios.

Solution of fiber Raman amplifier model using binary search equation-based adaptive artificial bee colony algorithm

Due to the need for high bandwidth, there is growing interest in distributed fiber Raman amplifiers (FRA). In addition to having wide bandwidth, FRAs have the advantages of a low noise factor and simplicity of use. However, the optimization of the wavelength and power values of the pump lasers to be used in FRAs for a broadband and flat gain region is an important problem to be solved. In this study, a distributed FRA system was set using 100 signals with a 50-km propagation distance and 8 pump signals in the opposite direction, which were gain-flattened. The attenuation coefficient of SMF-28 type optical fiber was used in the system. First, optimum pump wavelengths and power levels were found by the binary search equation based adaptive artificial bee colony algorithm. Then, the FRA boundary value problem (BVP) was solved with the MATLAB BVP solver. Finally, the analytical Jacobian matrix required for the solution of the equation was included in the system, and faster and more effective results were obtained. The results show that the gain ripple of 100 optical signals was 0.5 dB at the maximum.

A 140–220-GHz Low-Noise Amplifier With 6-dB Minimum Noise Figure and 80-GHz Bandwidth in 130-nm SiGe BiCMOS

This letter presents an ultra-broadband low-noise amplifier (LNA) with a 3-dB bandwidth of 80 GHz, covering the entire WR5 frequency band (140–220 GHz). Broadband gain and noise performance are obtained through optimal bias selection, dc coupling, and stagger tuning. <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$Y$ </tex-math></inline-formula> -factor noise figure (NF) measurement results are presented. A NF of 6.9, 6.1, and 8.2 dB is measured at 150, 180, and 210 GHz. Implemented in IHP 130-nm SiGe BiCMOS process, the LNA has a peak gain of 15.5 dB, while consuming 46-mW dc power.

Vertically Polarized Broadband Gain Stable Yagi– Uda Antenna for Millimeter-Wave Applications

A millimeter-wave endfire Yagi–Uda antenna based on a monopole fed by a substrate-integrated waveguide (SIW) line is presented in this letter. The antenna consists of two substrates assembled perpendicularly in a 3-D configuration. The vertical plane supports the driven monopole antenna and a group of passive parasitic monopoles, all printed as conductor strips. The horizontal layer contains the SIW feeding line, where the top metallic face acts as a mirror for the monopoles. According to the beam direction and the achieved gain, a parametric study is conducted to determine the number of elements. Two versions are proposed, studied, and experimentally validated. The first version with one arm achieved a <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$-$</tex-math></inline-formula> 10 dB impedance bandwidth of 23.5% (27.4–34.7 GHz) with a peak gain of 13.8 dBi. The second version with three arms of directors is proposed to achieve a stable gain of 15.1 <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$\pm$</tex-math></inline-formula> 0.5 dBi over 16% (27.1–32 GHz). The performance of the proposed antenna with relatively compact size makes it suitable for millimeter-wave systems.

Compact, Broadband and High Gain Uniplanar Quasi-Yagi Microstrip Antenna for End-Fire Radiation

This paper describes a uniplanar, compact, broadband, and high gain quasi-Yagi microstrip antenna to achieve radiation in the end-fire direction. The major elements of the proposed antenna include one element of each: reflector, ground plane (acts as another reflector), driven, and director. The concept of microstrip and Yagi-Uda antennas are coupled to lower the inter-element spacing, thus reducing the antenna dimensions along the boom length significantly. U-shaped reflector elements are used to reduce the lateral dimension of the antenna. The antenna's directivity is enhanced in the lower and upper-frequency bands with the help of reflectors and directors, respectively. A compact size of (0.52 × 0.22 × 0.009) has been achieved along with an impedance bandwidth of 46.5% for |S 11| < −10 dB and a peak gain of 6 dBi (with 1 dB variations) over the entire bandwidth. The novelty of the proposed uniplanar quasi-yagi MSA is proved by comparing the Figure of Merit (FoM) with the reported work. The proposed antenna is fabricated, and the measured results are in good agreement with the simulated results. The proposed uniplanar quasi-Yagi antenna is ideal for wireless applications that required end-fire radiation in 2G, 3G, 4G, Wi-Fi frequency bands, and portable direction-finding devices.

Wearable Polarization Conversion Metasurface MIMO Antenna for Biomedical Applications in 5 GHz WBAN

This paper presents a wearable metasurface multiple-input multiple-output (MIMO) antenna for biomedical applications in a 5 GHz wireless body area network (WBAN) with broadband, circular polarization (CP), and high gain. The physical properties of the MIMO antenna element and the principles of polarization conversion are analyzed in-depth using characteristic mode analysis. For the proposed MIMO antenna, the measured -10 dB impedance bandwidth is 34.87% (4.76-6.77 GHz), and the 3 dB axial ratio bandwidth is 22.94% (4.9-6.17 GHz). By adding an isolation strip, the measured isolation of the two antenna elements is greater than 19.85 dB. The overall size of the MIMO antenna is 1.67λ0 × 0.81λ0 × 0.07λ0 at 5.6 GHz, and the maximum gain is 7.95 dBic. The envelope correlation coefficient (ECC) is less than 0.007, with the maximum diversity gain greater than 9.98 dB, and the channel capacity loss is less than 0.29 b/s/Hz. The specific absorption rate (SAR) of the wearable MIMO antenna is simulated by the human tissue model, which proves that the proposed antenna conforms to international standards and is harmless to humans. The proposed wearable metasurface MIMO antenna has CP, broadband, high gain, low ECC, and low SAR, which can be used in wearable devices for biomedical applications.

Design and Challenges on mmWave Antennas: A Comprehesive Review

Researchers are keen to continue developing and investigating millimeter wave spectrum bands because these bands potentially provide broadband bandwidth for extremely high data transfer rates. This paper presents a comprehensive review of the recent millimeter wave antenna development, especially for 30-40 GHz, 60 GHz, and 140 GHz, with their characteristics, limitations, and challenges. Several previous millimeter wave antennas are introduced, including their broadband bandwidth, gain, feeding technique, substrate, and beamwidth. Based on their measured performances show that the millimeter wave antenna has great potential to support realizing the extremely high transfer data rate in wireless communication systems.

Horn Antenna Analysis and Simulation for the 18-40 GHz Frequency Band

An antenna is a type of transducer that converts radio signals into alternating electromagnetic waves before transmitting them into space. Polarization is a phase in the selection and installation of an antenna. It can send and receive signals. An antenna is a metal structure that transmits or receives electromagnetic radiation. The antenna, on the other hand, connects the directing device to free space. It sends a signal from the generator into space through transmission cables. High-frequency double-ridged horn (DRH) antennas for electromagnetic compatibility (EMC) are built using a special technique. When using this technique, at the beginning, consider a standard DRH antenna that operates between 1 and 18 GHz. A detailed sensitivity analysis of the 1-18 GHz DRH antenna's structural characteristics addresses some of the DRH antenna's weaknesses, notably in terms of its radiation pattern at higher frequencies. After that, the design is frequency scaled up to support a greater frequency range. This technology might be used to build a wideband DRH antenna that can operate between 18 and 40 GHz. Because the new antenna has a lower frequency ratio of 1:12.2 compared to the normal antenna's 1:18 ratio, we may choose the appropriate frequency window for scaling up. A voltage standing wave ratio (VSWR) of less than a single main lobe that is uninterruptedly oriented along the horn axis and a minimum of 10 dB of acceptable broadband gain are all necessary. The resulting design was used to produce a prototype antenna that was smaller than previous commercial antennas. The dimensions and design objectives were used to develop the prototype.

FSS Integrated High Gain Broadband Antenna

FSS Integrated High Gain Broadband Antenna

A Low-Profile Dual-Polarized Magneto-Electric Dipole Antenna for 5G Applications

A low-profile dual-polarized magneto-electric dipole (MED) is presented in this communication. The low profile was achieved using meander slots on the vertical magneto dipole, reducing the antenna height to 0.15λ0, where λ0 is the wavelength of the center frequency. Relatively, the proposed MED structure is easier to process and more stable than the traditional low-profile MED structure. The broadband performance for 5G Applications was realized based on MED structure, and the dual-polarization structure has wider coverage area and lower multipath transmission losses. Moreover, the orthogonal feeding structure provides a satisfying isolation between two ports. To verify the simulation results, a prototype of the proposed antenna was fabricated and measured. The results show that the overlapped operating frequency bandwidth with |S11| ≤ −10 dB, |S12| ≤ −20 dB was 36.8% from 3.1 GHz to 4.5 GHz, the peak gain reached 10.2 dBi, and the average gain exceeded 8.5 dBi. The measured 3 dB beamwidth with more than 44 degrees beamwidth was realized in both E-plane and H-plane. In addition, cross-polarization levels below −22 dB that covered the above frequency band were achieved. Compared with other MED antennas, in addition to broadband and high gain, the proposed antenna has the advantages of a low profile, easy processing, and low cost, which make it a competitive candidate for 5G applications.

Design of low profile, compact, high gain and broadband metasurface-based MIMO antenna for 5G/WiMAX/WLAN applications

ABSTRACT We have presented two-port MIMO antenna designs with low-profile material. Two different MIMO antenna designs are prepared and investigated to observe their effect on the gain, bandwidth, etc. The designs are prepared based on metasurface concepts with one design having a circular ring metasurface design and second having circular disk metasurface design. The designs are showing broadband response covering frequency range of 1.85 GHz to 4.27 GHz. The bandwidth of 2.320 GHz is achieved for this metasurface MIMO antenna design. The gain and directivity results show that highest gain of 5.88 dB and directivity of 6.39 dB are achieved with circular ring metasurface MIMO antenna design. Both metasurface MIMO antenna designs are fabricated, and measured results are also provided to verify the simulation results. The broadband and high gain design are applicable for 5G communication, WiMAX and WLAN applications.

Optical Supercontinuum Generation via Rotational and Vibrational Molecular Cavity Optomechanics

AbstractThe solid high quality (Q) factor whispering gallery mode microcavities are demonstrated as an excellent experimental platform for enhanced light–matter interactions, and are applied in the studies of nonlinear optics, quantum optics, and sensing. However, the interaction between the microcavity and liquid anisotropic molecule, which is unique for abundant vibrational and rotational degrees of freedom, is rarely studied. Here, the gap is bridged by filling an optofluidic microbubble resonator with carbon disulfide, and the related anisotropic molecular cavity optomechanics effects are investigated. Due to the enhanced coupling between the optical mode and the rotation/vibration of molecules, stimulated Rayleigh–Kerr/Raman–Kerr scattering effects are observed. Molecular cavity optomechanics provides a broadband gain for generating Stokes photons in high‐Q optical modes, and eventually allows quasi‐supercontinuum generation with a bandwidth of 436 nm under a low continuous laser pump power of about 10 mW. This work opens a new avenue for strong light–matter interactions by exploring rotational and vibrational molecular cavity optomechanics, which provides a promising platform for nonlinear optics, cavity‐enhanced molecular reorientation dynamics, and novel optical sources.

FSS embedded high gain ‘N’ shaped miniaturized broadband antenna

This research work represents a broadband (3.3 GHz − 17.85 GHz) high gain miniaturized (16 mm × 24 mm × 1.6 mm) microstrip patch antenna. Initially multiband property is achieved through ‘N’ shaped radiating patch surface and ‘I’ shaped ground plane surface. Finally broadband property is attained through better impedance matching by modifying feeding structure with a single step matching staircase structure. The presented antenna shows large −10 dB impedance bandwidth of 14.55 GHz with a percentage bandwidth of 138 %, Bandwidth Dimension Ratio (BDR) of 2970 and a peak gain of 4.45 dBi at 9.5 GHz. By embedding FSS (Frequency Selective Surface) structure having FSS unit cell dimension of 13 mm × 13 mm × 1.6 mm with the antenna at suitable distance, antenna gain has been elevated successfully across the entire operating frequency range (3.25 GHz–17.8 GHz). FSS coupled antenna exhibits highest gain improvement of 7.5 dBi at 3.5 GHz and peak gain of 9.1 dBi at 9.3 GHz. The FSS integrated antenna structure operates with elevated gain (peak gain of 9.1 dBi at 9.3 GHz) across the entire operating frequency range (3.25 GHz–17.8 GHz). All inclusive volume of the presented FSS coupled antenna is 52 mm × 52 mm × 21.2 mm, which can be successfully utilized in high gain broadband wireless applications. The antenna patch area miniaturization is calculated as 65 % with respect to lowest frequency of operation. The proposed FSS and antenna are developed and simulated by utilizing CST Studio Suite Software and equivalent circuit of the presented antenna is simulated utilizing ADS software. Both FSS and antenna are fabricated using inexpensive FR 4 substrate (1.6 mm thick, relative dielectric constant of 4.4 and loss tangent of 0.02) and Standard Microwave Test Bench is used to validate the antenna and composite antenna structure simulation results.

Broadband gain performance in the mid-IR using supercontinuum: 2.7 µm gain in high-purity Er3+doped tungsten tellurite glass fibers.

This paper presents an experimental study of broadband mid-IR amplification that is carried out, for the first time, to the best of our knowledge, in an erbium-doped tungsten tellurite fiber. A simple, robust supercontinuum source based on a tapered germanate fiber is developed as a seed input in the region of 1.5-3µm. We show that gain by a factor of 5 on one pass can be achieved in the 2.7µm range by pumping a low-cost, high-efficiency diode laser at 976nm using high-purity tellurite glass fibers.

Design and fabrication of reconfigurable, broadband and high gain complementary split-ring resonator microstrip-based radiating structure for 5G and WiMAX applications

Frequency reconfigurability and high gain are the two essential parameters of any antenna design, and these two parameters are successfully achieved in the antenna presented in this manuscript. The two RF switching diodes are used to alter the charge distribution over the patch region to achieve frequency reconfigurability. The fabrication carried out using the FR-4 material keeps the antenna cost low. The performance of the presented work is analyzed in terms of reflectance coefficient, total gain, bandwidth, directivity, fractional bandwidth, and normalized directivity. The novelty in the presented work is the filling of copper and liquid-based split-ring resonators in superstrate regions over the patch area to identify the performance improvement. The presented design provides the maximum frequency reconfigurability of 550 MHz, a minimum reflectance coefficient of −44.821 dB, and a maximum bandwidth of 462 MHz. The addition of superstrate layers will enhance the gain and maximum gain of 3.49 dB. The presented novel work will provide the multiband behavior which targets the different wireless communication applications like 5G communication and WiMAX.