Ultra-wideband Frequency Range Research Articles

Conformal Design of a High-Performance Antenna for Energy-Autonomous UWB Communication.

In view of the need for communication with distributed sensors/items, this paper presents the design of a single-port antenna with dual-mode operation, representing the front-end of a future generation tag acting as a position sensor, with identification and energy harvesting capabilities. An Archimedean spiral covers the lower European Ultra-Wideband (UWB) frequency range for communication/localization purposes, whereas a non-standard dipole operates in the Ultra High Frequency (UHF) band to wirelessly receive the energy. The versatility of the antenna is guaranteed by the inclusion of a High Impedance Surface (HIS) back layer, which is responsible for the low-profile stack-up and the insensitivity to the background material. A conformal design, supported by 3D-printing technology, is pursued to check the versatility of the proposed architecture in view of any application involving its deformation and tracking/powering operations.

Low Noise Amplifier with Improved Gain and Reduced Noise-Figure in 90nm CMOS Technology

A CMOS low noise amplifier (LNA) for ultra-wideband (UWB) wireless applications is presented in this paper. The proposed CMOS low noise amplifier (LNA) is designed using common-gate (CG) topology as the first stage to achieve ultra-wideband input matching. The common-gate (CG) is cascaded with common- source (CS) topology with current-reused configuration to enhance the gain and noise figure (NF) performance of the LNA with low power. The Buffer stage is used as output matching network to improve the reflection coefficient. The proposed low noise amplifier (LNA) is implemented using CADENCE Virtuoso Analog and Digital Design Environment tool in 90nm CMOS technology. The LNA provides a forward voltage gain or power gain (S21) of 32.34dB , a minimum noise figure of 2dB, a reverse-isolation (S12) of less than - 38.74dB and an output reflection coefficient (S22) of less than -7.4dB for the entire ultra-wideband frequency range. The proposed LNA has an input reflection coefficient (S11) of less than -10dB for the ultra-wideband frequency range. It achieves input referred 1-dB compression point of 78.53dBm and input referred 3-dB compression point of 13dBm. It consumes only 24.226mW of power from a Vdd supply of 0.7V.

A MEMS Ultra-Wideband (UWB) Power Sensor with a Fe-Co-B Core Planar Inductor and a Vibrating Diaphragm Capacitor.

The design of a microelectromechanical systems (MEMS) ultra-wideband (UWB) RMS power sensor is presented. The sensor incorporates a microfabricated Fe-Co-B core planar inductor and a microfabricated vibrating diaphragm variable capacitor on adhesively bonded glass wafers in a footprint area of 970 × 970 µm2 to operate in the 3.1–10.6 GHz UWB frequency range. When exposed to a far-field UWB electromagnetic radiation, the planar inductor acts as a loop antenna to generate a frequency-independent voltage across the MEMS capacitor. The voltage generates a coulombic attraction force between the diaphragm and backplate that deforms the diaphragm to change the capacitance. The frequency-independent capacitance change is sensed using a transimpedance amplifier to generate an output voltage. The sensor exhibits a linear capacitance change induced voltage relation and a calculated sensitivity of 4.5 aF/0.8 µA/m. The sensor can be used as a standalone UWB power sensor or as a 2D array for microwave-based biomedical diagnostic imaging applications or for non-contact material characterization. The device can easily be tailored for power sensing in other application areas such as, 5G, WiFi, and Internet-of-Things (IoT). The foreseen fabrication technique can rely on standard readily available microfabrication techniques.

Simple ultra-wide band antenna with double band rejection capability using double inclined elliptical split ring resonators

In this paper, CPW-Fed ultra wideband (UWB) planar monopole antenna loaded by double inclined elliptical split ring resonators (ESRRs) for double band-notch characteristics is introduced, examined, and fabricated. Two different ESRRs with different dimensions are printed in the antenna backside to notch two different frequencies in the UWB frequency range instead of using two ESRR pairs as usual. The ESRRs are then rotated and the corresponding return loss is studied. Different notch frequencies can be obtained by varying the ESRRs’ dimensions. Finite element method FEM and finite integration technique FIT are used to simulate the proposed structures through the usage of Ansys HFSS and CST MWS. Good agreement between both results has been obtained. Two different prototypes of the proposed antenna are fabricated and their reflection characteristics are measured. The first antenna is the UWB antenna with two straight ESRRs in which two notch frequencies at 5.3 GHz and 6.8 GHz have been obtained. The second antenna is the UWB antenna with two inclined ESRRs in which two notch frequencies at 5.1 GHz and 6.9 GHz have been obtained. In both cases, good agreement between simulated and measured results has been obtained and the discrepancies are due to fabrication and alignment errors. Also in both cases the proposed antennas notch WLAN and C-band wireless coexisted applications. A directive radiation pattern in E-plane and omnidirectional radiation patterns in the H-plane could be observed. Also the gain is suppressed in the notch frequencies in both cases. The group delay is nearly stable in the UWB frequency range, except at the notch frequencies, which is distorted sharply. So, the proposed antenna is a good candidate for the modern UWB systems.

High-performance and ultra-broadband vortex beam generation using a Pancharatnam–Berry metasurface with an H-shaped resonator

Vortex beams carrying orbital angular momentum (OAM) are expected to efficiently increase channel capacity in communication sectors, so ultra-broadband vortex beam generators with high performance are important in next-generation communication systems. Based on the concept of the Pancharatnam–Berry phase, we propose a metasurface with an H-shaped resonator for realizing vortex beam generation within an ultra-wideband frequency range from 7.3 to 21 GHz (relative bandwidth = 96.8%). The designed meta-atom can acquire high efficiency (efficiency ≥ 92%) conversion from the incident plane wave to the reflected vortex wave across the entire frequency band. To verify the performance of the proposed metasurface, a reflective array consisting of 18 × 18 single-layered elements with different rotated angles is simulated for generating the vortex beam with a topological charge of ±2. Through OAM spectral analysis, the left-handed components of the reflected electric fields and mode purity of the generated vortex beams under different frequencies are achieved and discussed in detail. Then the metasurface is fabricated and measured, and the numerical and experimental results coincide well, proving the effectiveness and high performance of the proposed design.

Frequency response measurement of high-speed photodiodes based on a photonic sampling of an envelope-modulated microwave subcarrier.

An approach to measuring the frequency response of high-speed photodiodes (PDs) is proposed and experimentally demonstrated based on employing an ultrashort optical pulse train to sample an envelope-modulated microwave subcarrier. Through up-and-down conversion sampling, a varying frequency component and a fixed low frequency component can be obtained, where the varying frequency component probes the ultra-wideband response information of PD. Through measuring the relative amplitude between the two frequency components, the frequency response of the PD at the any frequency within ultra-wideband frequency range can be calculated by taking the response at the fixed low frequency component as a reference. Thereinto, the frequency response of the electro-optic modulator is cancelled out, and the uneven comb intensity introduced by the ultrashort optical pulse train can be corrected by choosing the specific frequency of the microwave subcarrier. In the proof-of-concept experiment, the self-calibrated frequency response measurement of a commercial PD is demonstrated by employing an optical pulse train with a repetition rate of 9.954 GHz and an electro-optic frequency sweeping up to 4.977 GHz. The frequency measurement range is achieved up to 49.77 GHz, and the frequency resolution reaches 300 kHz in the rough measurement and 10 Hz level in the fine measurement. The consistency between the proposed method and conventional methods proves the ultra-wideband and hyperfine frequency response measurement of PDs.

A UWB Antenna Array Integrated with Multimode Resonator Bandpass Filter

This paper presents a novel design of a modified ultrawideband (UWB) antenna array integrated with a multimode resonator bandpass filter. First, a single UWB antenna is modified and studied, using a P-shape radiated patch instead of a full elliptical patch, for wide impedance bandwidth and high realized gain. Then, a two-element UWB antenna array is developed based on this modified UWB antenna with an inter-element spacing of 0.35 λL, in which λL is the free space wavelength at the lower UWB band edge of 3.1 GHz, compared to 0.27 λL of a reference UWB antenna array designed using a traditional elliptical patch shape. The partial ground plane is designed with a trapezoidal angle to enhance matching throughout the UWB frequency range. The mutual coupling reduction of a modified UWB antenna array enhances the reflection coefficient, bandwidth, and realized gain, maintaining the same size of 1.08 λ0 × 1.08 λ0 × 0.035 λ0 at 6.5 GHz center frequency as that of the reference UWB antenna array. The UWB antenna array performance is investigated at different inter-element spacing distances between the radiated elements. To add filtering capability to the UWB antenna array and eliminate interference from the out-of-band frequencies, a multimode resonator (MMR) bandpass filter (BPF) is incorporated in the feedline while maintaining a compact size. The measurement results showed a close agreement with simulated results. The proposed UWB filtering antenna array design achieved a wide fractional bandwidth of more than 109.87%, a high realized gain of more than 7.4 dBi, and a compact size of 1.08 λ0 × 1.08 λ0 × 0.035 λ0 at 6.5 GHz center frequency. These advantages make the proposed antenna suitable for UWB applications such as indoor tracking, radar systems and positioning applications.

A Common-Gate Current-Reuse UWB LNA for Wireless Applications in 90 nm CMOS

In this paper, a CMOS low noise amplifier (LNA) for ultra-wideband (UWB) wireless applications is presented. The proposed CMOS LNA is designed using common-gate (CG) topology at the first stage to achieve ultra wideband input matching. The common-gate has been cascaded with common-source (CS) current-reused configuration to enhance the gain and noise figure (NF) performance of the LNA with low power consumption. In order to ensure maximum power flow from CG input stage to gm boosted CS current-reused stage, parallel-series LC matching has been used. The output-matching network is used to improve the output reflection coefficient. The LNA is designed using standard 90 nm CMOS process for 3.1–10.6 GHz UWB. It exhibits a power-gain (S21) of 19.2–20.8 dB, an NF of 2.3–3.7 dB, a reverse-isolation (S12) of less − 53.8 dB and an S22 of less than − 6 dB for the entire UWB frequency range. The proposed LNA has an input reflection coefficient (S11) of less than − 10.6 dB for 3.1–10.6 GHz. It achieves input 1-dB compression point (P1dB) of − 17 dBm at 6 GHz and input third-order intercept point (IIP3) of − 8 dBm, while it consumes only 5.05 mW of power from a Vdd supply of 0.7 V.

Performance and Analysis of UWB Aesthetic Pattern Textile Antenna for WBAN Applications

This article proposes a new aesthetic pattern-three petal flower patch antenna that operates at Ultra Wide Band (UWB) for Wireless Body Area Network (WBAN) applications. The flower structure consists of three petals and a center circle patch with the partial ground plane at the bottom. A double-sided copper-coated conductive fabric, which is 0.08 mm thick, having a surface resistivity of 0.05 Ω/square, serves as the antenna patch and ground material. This conductive patch is placed in a denim jeans material with 1mm thick that forms the substrate. The utilization of a two-layer substrate and partial ground method enhances the impedance bandwidth of the antenna. The size of the antenna is 60 mm × 60 mm × 2.16 mm. The reflection coefficient, gain, efficiency, radiation pattern, and effects of bending were the various parameters analyzed for the flower antenna. The antenna radiates from 3 to 12 GHz, which covers the entire UWB frequency range from 3.1 to 10.6 GHz assigned by Federal Communications Commission (FCC). The measurement results validate the performance of a flower patch antenna.

Simulation and Measurement Data-Based Study on Fat as Propagation Medium in WBAN Abdominal Implant Communication Systems

This paper presents comprehensive study on fat as propagation medium in abdominal implant communication system at low ultrawideband (UWB) frequency range 3.75-4.25 GHz. The main aim is to investigate how signal propagates through visceral and subcutaneous fat layers and how that information can be exploited in implant communication systems. The study is conducted using different methods: electromagnetic simulations, power flow analysis, propagation path calculations and radio channel measurements with animal meat pieces. Simulations are conducted using layer models and anatomical voxel models having different sizes. Results of channel simulations are verified with propagation path calculations. Power flow analysis on cross-cuts of the voxel models is conducted to investigate how the signal propagates inside the tissues. Furthermore, measurements using different animal meat pieces are performed to evaluate the impact of fat constitution on channel characteristics. It is found that similar tendency on fat propagation is seen in the evaluations with different methods. It is also observed that channel attenuation depends not only on the types and thicknesses of the tissues between transmitter and receiver antennas, but also how the tissues, especially fat, is located between the antennas. Channel attenuation difference between different voxels is maximum 14 dB in the studied antenna locations. Furthermore, propagation channel is evaluated with measurements using pork meat having different fat and muscle constitutions. It is found that antenna location respect to fat layers has clear impact on the channel strength although the fat tissue is not directly above the in-body antenna. The difference is noted to be 3-15 dB especially on the side peaks of channel impulse response. The knowledge on fat as a propagation medium is crucial when designing medical monitoring or implant communication systems. Location of antennas/sensor nodes for the monitoring devices can be established so that propagation through fat layer can be exploited.

Ultra-Wideband Flat Metamaterial GRIN Lenses Assisted With Additive Manufacturing Technique

This article presents the designs of ultrawideband microwave flat gradient index (GRIN) lenses, which realizes over a 108% fractional bandwidth (12-40 GHz). The frequency-independent ray optics method is employed to determine the radially varying permittivity profile of the lenses. The challenge of realizing such a radially varying profile and the limitations in dielectric material choices are overcome by two additive-manufacturing-aided approaches: 1) partially infilled dielectrics with a varied periodicity, which ensures the lens performance at the higher end of the frequency range and 2) artificially engineered dielectrics (AED) with subwavelength-scale metallic inclusions, which enables-high permittivity dielectrics and leads to benefits of thickness and mass reduction for the GRIN lenses. Measured results demonstrate that the GRIN lenses improve the gain of open-ended waveguide sources by 8.7-15.6 dB over a wide frequency range from 12 to 40 GHz, with the realized gain of up to 23.6 dBi. Both the simulation and measurements of the presented design confirm the potential of implementing the proposed GRIN lens design in high directivity and beamforming antenna applications, across an ultrawideband frequency range.

Compact Rack Shaped MIMO Dielectric Resonator Antenna with Improved Axial Ratio for UWB Applications

In this paper, a rack shaped two radiator element multiple input multiple output (MIMO) dielectric resonator antenna (DRA) is reported with improved axial ratio (AR) characteristics for ultra-wideband applications. The proposed MIMO antenna structure is implemented with the help of two rectangular shaped radiator elements which are further changed into rack shaped dielectric resonator (DR) that support three modes HEM111, HEM121, and HEM212, at 7.3, 9.3, 10.74 GHz respectively. The approach of rack shaped DRA has improved the transmission coefficient for the UWB range. Inverted T-shaped metallic strip apart from giving elliptically polarized (EP) characteristics also helps in controlling both the axial ratio bandwidth and impedance bandwidth (101.87%). The simulated and measured outcomes validated that the proposed antenna can be utilized for 3.54–10.89 GHz ultra-wideband (UWB) frequency range. The MIMO diversity parameters are implemented as ECC ≤ 0.0059, DG ≥ 9.93 dB, TARC (0, 30, 60, 90, 120, 150, and 180) degrees, GD (0.96 to − 2.1 ns) and CCL (≤ 0.4 except of 8.8–9.6 GHz). All the obtained MIMO antenna parameters are within the acceptable limit and also provides high data rate applications in C and X bands.

A Planar Ultrawideband Patch Antenna Array for Microwave Breast Tumor Detection.

In this paper, a compact planar ultrawideband (UWB) antenna and an antenna array setup for microwave breast imaging are presented. The proposed antenna is constructed with a slotted semicircular-shaped patch and partial trapezoidal ground. It is compact in dimension: 0.30λ × 0.31λ × 0.011λ, where λ is the wavelength of the lowest operating frequency. For design purposes, several parameters are assumed and optimized to achieve better performance. The prototype is applied in the breast imaging scheme over the UWB frequency range 3.10–10.60 GHz. However, the antenna achieves an operating bandwidth of 8.70 GHz (2.30–11.00 GHz) for the reflection coefficient under–10 dB with decent impedance matching, 5.80 dBi of maximum gain with steady radiation pattern. The antenna provides a fidelity factor (FF) of 82% and 81% for face-to-face and side-by-side setups, respectively, which specifies the directionality and minor variation of the received pulses. The antenna is fabricated and measured to evaluate the antenna characteristics. A 16-antenna array-based configuration is considered to measure the backscattering signal of the breast phantom where one antenna acts as transmitter, and 15 of them receive the scattered signals. The data is taken in both the configuration of the phantom with and without the tumor inside. Later, the Iteratively Corrected Delay and Sum (IC–DAS) image reconstructed algorithm was used to identify the tumor in the breast phantom. Finally, the reconstructed images from the analysis and processing of the backscattering signal by the algorithm are illustrated to verify the imaging performance.

Experimental verification of super-compact ultra-wideband (UWB) polarization and incident angle-independent metamaterial absorber

AbstractIn this paper, a super-compact ultra-wideband (UWB) metamaterial absorber (MMA) is presented. The absorber design consists of an inverted L-shaped structure and a diagonal rectangular-shaped structure. The capacitive coupling between these two structures not only provides UWB nature but also provides a super-compact absorber design. The dimension of the unit cell arrangement is 5 × 5 mm2 and printed on a low-cost FR-4 substrate of thickness 1.54 mm (0.061λlowest). The design absorber provides more than 97% absorptivity from 12 to 21 GHz for normal incidence electromagnetic (EM) wave. However, the proposed MMA has a full width at half maximum absorption bandwidth of 11.71 GHz from 10.34 to 22.05 GHz. Moreover, the surface current distributions have been analyzed to understand the absorption mechanism of the MMA. The stability of the proposed design is validated with different incident angles (for TE and TM modes) and different polarization angles. Finally, the absorber design is fabricated and verified experimentally. Furthermore, the UWB frequency range, high absorption, ease in design and fabrication, and cost-effective make it suitable for different quality applications in stealth technology, thermal imaging, radar detection, antenna systems, and other EM devices.

A compact flower slotted dual band notched ultrawideband antenna integrated with Ku band for ultrawideband, medical, direct broadcast service, and fixed satellite service applications

AbstractA compact flower slotted antenna (FSA) for dual band eliminated ultrawideband (UWB) integrated with Ku band applications is proposed. The basic FSA with modified ground structure is utilized for obtaining fractional bandwidth of 137% (3.45‐18.45 GHz). The dual band eliminated frequencies are achieved by a via hole to eliminate 5.39 to 5.90 GHz (upper WLAN band) frequencies and by utilizing symmetrical inverted L‐shaped parasitic elements to notch 7.30 to 7.75 GHz (downlink of X‐ band satellite communication link) frequencies. The FSA is having a compact size of 16 × 22 mm2 printed on low cost FR‐ 4 substrate with two band notched characteristics, nearly omnidirectional radiation characteristics and stable gain over UWB frequency range makes it suitable for portable UWB systems.

Design of a 3D Printed UWB Antenna for a Low-Cost Wireless Heart and Respiration Rate Monitoring

This paper introduces an ultra-wideband (UWB) horn antenna for a low-cost wireless heart and respiration rate monitoring that is manufactured by a 3D printing technology. The proposed design operates within 3.1-10.6 GHz. The horn antenna is designed within the 15-dB gain which is sufficient to be used in medical system. The horn was designed to calculate the gain in MATLAB using an approximation method and simulated using CST Microwave Studio. The proposed antenna is 4-6 GHz (G-Band) operating. A printed antenna which is supported by WR-187 rectangular waveguide is fabricated using low cost polylactic acid (PLA). The surface is then metalized using copper tape on the inside. The simulation result of reflection coefficient for different conductivity and thickness of coating metal is compared, the developed 3D printed antenna successfully operated within given frequency range of 3-11 GHz which covered the ultra-wideband frequency range.

A slotted UWB monopole antenna with truncated ground plane for breast cancer detection

In the last decade, a new dawn for research on microwave imaging (MI) has been observed in the medical domain specially in the breast cancer diagnosis, since it offers many advantages over current imaging systems like computed tomography (CT), X-ray radiography etc. Microwave imaging system (MIS) provides a suitable platform for in-depth inspection of breast tissues. It helps in identification and localisation of morphological changes in these tissues. The emerging Ultrawideband (UWB) MI gives better results due to its non-ionizing signals which operate over the frequency ranging from hundreds of Megahertz (MHz) to tens of Gigahertz (GHz). In these systems, antennas play a significant role in establishing a sensor network. Hence, its optimization is very crucial because the device is placed at close proximity to the human body. In this paper, a miniaturised monopole patch antenna which operates at UWB frequency range with a microstrip feed line is proposed. The design is composed of a small rectangular patch with dimensions 0.17λ×0.25λ×0.02λ (where λ is wavelength calculated at lower operating frequency 4.8 GHz). It has four corner cuts and a centrally located square slot with a truncated ground-plane for achieving UWB properties. The proposed antenna has the measured fractional bandwidth of 141%(3.22-11.92GHz) with linearly increasing gain ranging from (1.4 to 6.43 dBi). The detailed time domain analysis is done to prove the efficacy of antenna for signal propagation. The advantage of proposed antenna is that it has low profile, compact size, easy to design which can be employed in MI breast cancer detection.

Butterfly Shaped Printed Monopole Antenna for Ultra Wide Band Applications

In this paper, a microstrip line fed butterfly shaped monopole UWB antenna is proposed for wireless applications. The wings of butterfly shaped monopole antenna is formed by adding two rotated ellipse of same radius symmetrically placed about the centre of feeding line. The proposed antenna exhibits impedance bandwidth of 3.1-11.9 GHz which covers the whole ultra-wideband frequency range from 3.1-10.6 GHz. The performance is characterised in terms of VSWR, radiation patterns, impedance bandwidth and gain. The proposed antenna can be used for various UWB applications like high performance in noisy environment, low transmission power, cost effectiveness and large channel capacity.

Band-Notched Antipodal Vivaldi Antenna using Edge-Located Vias Mushroom EBG Structure for Ultra Wideband Applications

An Ultra wideband (UWB) Antipodal Vivaldi Antenna operating at 2.78 GHz to more than 12 GHz with dual notch band attributes is designed for application in ultra-wideband. The proposed double-layered antenna is designed on a low cost FR-4 dielectric material with combined thickness of 2.1mm. Two edge-located vias mushroom type EBG metamaterial structures were incorporated within a conventional antipodal Vivaldi antenna (AVA) in between the two substrate layers and below the feeding line, to realize the proposed antenna. Using the band gap property of the EBG structure, two notch bands were created within the ultra wideband frequency range of the antenna for WiMAX IEEE 802.16 application at 3.18 – 3.80 GHz and WLAN IEEE 802.11a application at 5.13 – 5.80 GHz. Simulation results showed a almost stable directional radiation pattern in the entire frequency range except in the two notch bands, having a peak realize gain of 7.69 dBi at 6.5 GHz. Additionally, surface current distribution and far-field radiation patterns are also studied to characterize the achievement of the presented antenna.

Design of CPW-fed MIMO Antenna for Ultra-Wideband Communications

This paper presents a compact multiple input multiple output (MIMO) antenna design with good isolation for ultra-wideband (UWB) applications. The proposed antenna contains two identical monopoles that are placed parallel to each other and which are fed by a 50-ohm coplanar waveguide (CPW). The MIMO antenna is fabricated on a low-cost flame resistant 4 (FR4) substrate with an overall size of 36 × 36 × 1.6 mm3. The designed antenna has a good wideband impedance matching of |S11| <-10 in the UWB frequency range from 3.1 to 14.9 GHz and a good isolation about 13.7 dB in the whole UWB band. The prototype of the design is fabricated and measurement is carried out in order to validate the simulated results. The proposed antenna exhibits an envelope correlation coefficient (ECC) less than 0.01 and a diversity gain (DG) more than 9.9 dB, which means that the antenna has a good performance and good candidates for UWB applications.