Ultra-wideband Wireless Communication Systems Research Articles

Design and analysis of metasurface-based CPW-Fed UWB MIMO antenna for wireless communication systems

A compact 4-port coplanar waveguide (CPW) fed ultra-wideband (UWB) multiple-input-multiple-output (MIMO) antenna with enhanced isolation is proposed to operate from 3.66 GHz to 16.61 GHz with 127.78% impedance bandwidth. The proposed antenna system consists of 4 orthogonal arrays of monopole antennas improved by four iterations. The UWB characteristic of the antenna is obtained from an improved monopole antenna fed by CPW. The final MIMO antenna is machined on a Rogers 4003C substrate with dimensions of mm3. The orthogonal arrangement of antennas brings about the polarization diversity and certain isolation of MIMO antennas. Four rows of orthogonal metasurface elements with via holes and the ring of the backplane further improve the isolation between antenna elements in the MIMO system. The MIMO antenna has an impedance bandwidth of 12.95 GHz with dB and good isolation ( dB and dB). In particular, S31 is always less than −25 dB at frequencies greater than 6 GHz. The measured results of MIMO antenna agree with the simulated results. The optimized MIMO antenna has excellent performance in many aspects, such as UWB, compact size, omnidirectional radiation, enhanced isolation and high efficiency, which means that it has application potential in UWB wireless communication systems.

An 8-18 GHz 90° Switched T-Type Phase Shifter.

This paper proposes a novel 8-18 GHz 90° switched T-type phase shifter (TPS). In contrast to the conventional TPS, the proposed TPS adds a compensation capacitance to greatly enhance the phase shifting capacity. Moreover, the designed structure also integrates a filtering compensation network, which can effectively achieve a flat relative phase shift in a wide band. The proposed 90° TPS is fabricated using 0.15 μm GaAs pHEMT technology. The TPS achieves homogeneous phase shift at 8-18 GHz, with the measured phase error of less than ±1.5°. The insertion loss of the proposed phase shifter is 1.3-2.6 dB, and the chip size is merely 0.53 × 0.86 mm2. Thanks to these excellent performance characteristics, the designed phase shifter is well-suited for ultra-wideband wireless communication and radar systems.

A UWB bandpass filter based on elliptical open stub-loaded resonator and dumbbell-sided cross-circle DGS

An Ultra-wideband (UWB) bandpass filter (BPF) based on an elliptical open stub-loaded resonator (EOSLR) and dumbbell-sided cross-circle (DSCC) defected ground structure (DGS) is proposed in this paper. The measured results show that the 3 dB bandwidth of the filter is 3.49 ∼ 11.04 GHz, the skirt factor (S.F) is 0.844, the upper stopband rejection is greater than 20 d B at 11.70 ∼ 26.80 GHz, and the stopband width is 15.1 GHz. The proposed filter has the advantages of high selectivity and extremely broad upper stopband and it can be applied in UWB Wireless communication system.

METHODS AND TOOLS FOR ASSESSING THE LEVEL OF NOISE IMMUNITY OF WIRELESS COMMUNICATION CHANNELS

The subject of this article is the process of increasing the noise immunityof wireless channels in the construction or operation of modern digital communication systems (DCS), when the transmission of digital information significantly complicates the presence of interference and distortion in the communication channel. The aim is analysis and development of methods for ensuring stable and reliable operation of ultra-wideband wireless communication system in the conditions of interference and distortion of information in wireless communication channels. The task is creation and implementation of practical recommendations for improving the level of secrecy and quality of information circulating in the communication channel; development of criteria for quality, information efficiency and noise immunityof DCS wireless communication channels in the conditions of interference of natural and artificial origin. The methods used: methods of analytical modeling and the theory of potential noise immunity. The following results were obtained. The feasibility of assessing the DCS efficiency by two indicators - energy and frequency efficiency, which are the components that make up the overall integral indicator of informational efficiency was shown. It was proposed to evaluate the DCS efficiency by comparing the indicators of informational efficiency of the inverse and reference systems, using the Shannon limit as an ideal ratio of energy and frequency efficiency. On the basis of the theory of potential noise immunity it was shown that it is possible to operate wireless communication channels in conditions when the level of information signal and noise have the same value. Conclusions. It is shown that the use of the technology of supersmooth signals allows to carry out wireless redundant transmission of information with low impromptu capacity. Moreover, the efficiency of digital communication systems significantly increases due to the creation of an ensemble of complex signals through one-time encoding and modulation, which expands its information base, ensuring coverage and energy efficiency in a double symmetric channel. This enables the fullest possible utilization of the channel's Shannon capacity with high integrity of information transfer without a significant increase in the signal-to-noise ratio at the receiver's input. An integral indicator of informational efficiency of the wireless DCS communication channel is provided. It enables real-time integral assessment of link quality and optimal routing in a mobile peer-to-peer network – MANET.

A Compact CPW-Fed Ultra-Wideband Multi-Input-Multi-Output (MIMO) Antenna for Wireless Communication Networks

In this article, a compact coplanar waveguide (CPW) technique based ultra-wideband multiple-input-multiple-output (MIMO) antenna is proposed. The design is characterized by a broad impedance bandwidth starting from 3 GHz to 11 GHz. The overall size of the MIMO design is <inline-formula> <tex-math notation="LaTeX">$60\times60$ </tex-math></inline-formula> mm² (<inline-formula> <tex-math notation="LaTeX">$1.24\times 1.24\,\,\lambda _{g}^{2}$ </tex-math></inline-formula> &#x0040; 3 GHz) with a thickness of 1.6 mm. To make the design ultra-wideband, the proposed MIMO antenna design has four jug-shaped radiating elements. The design is printed on a FR-4 substrate (relative permittivity of <inline-formula> <tex-math notation="LaTeX">$\varepsilon _{r} = 4.4$ </tex-math></inline-formula> and loss tangent of <inline-formula> <tex-math notation="LaTeX">$\mathrm {tan}\delta = 0.025$ </tex-math></inline-formula>). The polarization diversity phenomenon is realized by placing four antenna elements orthogonally. This arrangement increases the isolation among the MIMO antenna elements. The simulated results of the ultra-wideband MIMO antenna are verified by measured results. The proposed MIMO antenna has a measured diversity gain greater than 9.98, envelope correlation coefficient (ECC) less than 0.02, and good MIMO performance where the isolation is more than &#x2212;20dB between the elements. The group delay, channel capacity loss (CCL), and the total active reflection coefficient (TARC) multiplexing efficiency and mean effective gain results are also analyzed. The group delay is found to be less than 1.2ns, CCL values calculated to be less than 0.4 bits/sec/Hz, while the TARC is below &#x2212;10dB for the whole operating spectrum. The proposed design is a perfect candidate for ultra-wideband wireless communication systems and portable devices.

Ku대역과 밀리미터 대역의 광대역 무선통신 시스템을 위한 소형 슬롯 6각 구조의 패치 안테나

본 논문에서는 초광대역의 소형 슬롯 6각 구조의 패치 안테나가 12×9×0.787 ㎣ (1.64λ×1.23λ×0.107λ)로 설계되었다. 본 논문에서는 위성통신과 66.67%의 중심 주파수 비 대역폭을 가지는 미래 ㎜-Wave 어플리케이션을 위해 (30 ~ 52) ㎓의 대역보다 더 넓은 초광대역 통신을 위해 슬롯 6각 구조의 ground plane이 Ku대역 주파수(17.608 ~ 19.64) ㎓에서 동작되도록 제시했다. 안테나는 37 ㎓의 ㎜-Wave 주파수 대역을 포함하여 다양한 주파수에서 공진한다. 제안된 안테나의 최대 이득은 6.282 ㏈이다.

Design of an ultra-wideband dual-polarized array antenna

In order to meet the requirements of ultra-wideband wireless communication system applications, this paper studies an ultra-wideband dual-polarization strongly-coupled array antenna. The array element is composed of two pairs of connected printed dipoles orthogonally. The feed network is constructed by the Marchand Balun and the Wilkinson power splitter and realizes the balanced feed, the impedance transformation and common mode resonance suppression. Simulated and measured results show that the proposed antenna achieves an impedance bandwidth of 1.5 GHz to 4.0 GHz, and an E-plane beam scanning range ±60°, H-plane beam scanning range ±50°, and the antenna structure is simple, and is suitable for the applications of dual-polarization wide-angle scanning phased array antenna system.

Isolation Enhancement between Ports of a Compact Ultra-wideband MIMO Antenna

In this paper, a novel compact multiple-input multiple-output (MIMO) antenna with enhanced port isolation is proposed for ultra-wideband (UWB) applications. The UWB MIMO antenna contains two coplanar annular monopoles etched on the front side of the FR-4 substrate. The dielectric substrate has a relative permittivity of 4.4 and a size of 80 mm × 40 mm × 1.6 mm. The irregular ground is printed on the back side of the substrate. In order to enhance the port isolation between the two monopoles, the expanded ground is exploited in the proposed design. In addition, the ground is etched with some slots to achieve good impedance matching. Both the simulated and measured results show that the proposed antenna achieves good impedance matching as well as high port isolation over the entire UWB band. Moreover, the proposed antenna has good spatial diversity characteristics. In summary, the proposed UWB MIMO antenna can be well applied to the ultra-wideband wireless communication system.

Single Feed Dual Polarized Patch Antennas for Ultra-Wideband Applications

In this paper, the design of a single feed dual polarized patch antenna for ultra wideband applications is presented. The two single feed dual-polarized patch antennas are designed to operate at lower band and upper band of the ultra-wideband frequency range. These antennas together operate at the entire frequency range of ultra wideband. The designed antennas are optimized using CST Microwave Studio. The antenna prototypes are fabricated and measured. Various input and radiation parameters of the designed antennas are presented and analyzed. The bandwidth of lower band antenna is 3.15 GHz to 6.48 GHz and of the upper band antenna is 5.92 GHz to 10.6 GHz. The antennas together covers the entire frequency band of ultra-wideband that is from 3.15 GHz to 10.6 GHz. The proposed antennas are simple and easy to fabricate with low cost. The radiation patterns of the designed antenna are omnidirectional and the other parameters are acceptable as per the standards. The proposed antennas are suitable for dual polarized ultra-wideband wireless communication systems.

A broadband circularly polarized monopole antenna

A compact modified C-shaped monopole antenna with broadband circular polarization is proposed, fabricated and measured. The antenna structure is simple and only consists of combined modified C-shaped radiation patch and an improved ground plane with the overall size of 25 × 25 × 1 mm3. By cutting the corner on the modified C-shaped patch and adding triangular stubs on the ground plane, the wide impedance bandwidth and axial ratio bandwidth are achieved. The design process of the antenna is given, and the circular polarization mechanism of the circularly polarized antenna is analyzed from the surface current distributions. The measured impedance bandwidth is 95.2% (4.4-12.4 GHz) with return loss better than 10 dB, and the measured 3 dB axial ratio bandwidth is 96.8% (4.42-12.72 GHz). The peak gain is above 3.0 dBi within the working band, which indicates that it is suitable for application of ultra-wideband (UWB) wireless communication systems and satellite communication systems.

UWB active antenna using dielectric resonator

AbstractThis article presents the experimental study of a ultra‐wideband (UWB) active antenna comprising of a chaotic oscillator coupled to a dielectric resonator antenna. Wideband spectrum properties of chaotic signals are used to design an UWB active antenna. In contrast to classical active UWB antenna designed using patch, the proposed active antenna is capable of enhancing the bandwidth, easy to integrate with the oscillator and is small in size. The proposed UWB antenna using DR can be employed in UWB wireless communication systems.

Fast Startup of LC VCOs Using Circuit Asymmetries

An LC VCO whose design includes deliberate circuit mismatches is presented. It is shown that such mismatches can reduce the oscillation start-up time due to a common-mode disturbance simultaneous with the turn-on of the tail current. The use of this technique is applied to a low-power transmitter for an ultra-wideband wireless communication system using the on–off keying modulation scheme. Measurements using a 0.18- ${\mu }\text{m}$ CMOS technology with a 4.2-GHz carrier frequency demonstrate the technique.

A bandwidth enhancement for metamaterial microstrip antenna

AbstractA bandwidth enhancement for metamaterial microstrip antenna is presented for ultra‐wideband (UWB) applications. The metamaterial antenna consists of irregular figures etched on the upper patch periodically and a planar metallic ground carved by grid patterned gaps on the bottom patch. The overall dimension of the proposed antenna is mm3. Experimental results show that the relative impedance bandwidth (–10 dB) of the proposed antenna is 168.3% with the ranging from 2.9 to 33.7 GHz, whose relative bandwidth is improved by 38.9–121.9% than the previously reported wideband ones. Its simulated reflection coefficient has a good agreement with the measured one, and its gain varies from 1.30 to 7.17 dB, meanwhile, it has a maximum radiation efficiency of 95.6% in the operating frequency band. Besides, the end‐fire directional radiation in the high frequency band is observed. Thus, the proposed antenna could be a potential candidate for UWB wireless communication systems.

Compact circular-patch-based bandpass filter for ultra-wideband wireless communication systems

Ultra-wideband (UWB) is a radio technology that enables low-power-level, short-range, and wide-bandwidth communication, and it has been widely applied in personal area networks, precision geolocation, medical, surveillance, and vehicular radar systems. Since Federal Communications Commission released the unlicensed use of the UWB range (3.1–10.6GHz), a significant attention has been paid to the development of UWB devices, particularly UWB bandpass filters. In this paper, we propose a novel UWB bandpass filter based on circular patch resonator that is grounded by via and perturbed by slits and defected ground structures. The resonator’s behaviour is analysed in detail and it is shown that its specific configuration allows a flexible control of the three lowest resonant modes, which are used to form UWB passband. To demonstrate the potential of the resonator, a UWB filter has been designed, fabricated, and measured. The filter is characterized by the insertion loss lower than 1dB and return loss higher than 17dB within the passband, as well as by very small group delay variation of only 0.07ns. Also, the filter exhibits suppression higher than 19dB up to 30GHz, and very small overall dimensions of only 0.31λg×0.31λg, and thus it outperforms other published UWB filters.

An Efficient Narrowband Interference Suppression Approach in Ultra-Wideband Receiver

Ultra-wideband (UWB) radio will be sharing the propagation environment with other pre-existing wireless systems, some possibly creating UWB multiple access interference, and others creating narrowband interference in the UWB radio bands. The Federal Communications Commission regulations have set conditions that limit the interference from the UWB radiators to other wireless systems, however, the issue of eliminating interference to the UWB radios from the pre-narrow band interference existing system is left to the ingenuity of the UWB radio designer. To optimize the performance of UWB wireless communication systems deteriorated by strong narrowband interferences, a high-efficiency interference suppression scheme is proposed in this paper. The closed-form weight coefficient iteration expression of basic adaptive notch filter cell with two constrained zero-pole pairs is derived. For multiple narrowband interferences case, a high-order cascaded adaptive interference suppression scheme is also presented. The simulation result demonstrates that the proposed narrowband interference suppression approach has excellent suppression effects to narrowband interferences in UWB systems, since a significant signal to noise ratio improvement is obtained. In addition, the proposed narrowband interference suppression algorithm is particularly fit for low-cost UWB wireless reception connected with Rake combining techniques.

A 50 MHz ~ 10 GHz, 3.3 dB NF, +6 dBm IIP3 resistive feedback common source amplifier for cognitive radio application

Cognitive radio is a smart ultra-wideband wireless communication system that is capable of optimizing the usage of the available frequency spectrum. In this work, an ultra-wideband low noise amplifier with an operating bandwidth from 50MHz to 10GHz with integrated resistive feedback and π-matching network is presented. The amplifier is designed to self-bias via the feedback path to optimize the chip area consumption. The input signal is sourced to two common-source amplifiers to achieve the input matching configuration and subsequently cascaded to another common source amplifier with resistive termination in achieving the output matching. On-chip inductors were adapted to improve the high frequency response and to extend the bandwidth up to 10GHz. Measured results show that the input and output matching are better than −10dB with a gain variation of 10.32–13.28dB, noise figure variation of 3.29–6dB, and a third order intercept point ranging from −3.2 to +6dBm in a frequency span of 50–10GHz on a CMOS 0.13µm platform. The physical layout occupies 0.77mm2 chip area with the bondpads intact and consumes 31.2mW of DC power from 1.2V DC supply headroom.

Single‐layer differential CPW‐FED UWB antenna with common‐mode suppressed and band notched applications

ABSTRACTA single‐layer differential coplanar waveguide (CPW) fed antenna is proposed for common‐mode suppressed and WLAN band notched ultra‐wideband (UWB) applications. The UWB nature is generated by the stepped slot radiators and a pair of differential stepped CPW feeding lines. When two ports of the antenna are fed with common‐mode signals, the radiator cannot be excited and common‐mode suppression is obtained. Moreover, a pair of U‐shaped slits and stubs are etched on the CPW lines and stepped slots to earn a notch band characteristic. Then, to validate the presented antenna, a prototype antenna is fabricated and tested. The proposed antenna shows experimentally differential reflection coefficients −10 dB bandwidth of 122.6% (2.54 − 10.6 GHz). A measured band notch at 5.1–5.9 GHz for WLAN band is also obtained. Moreover, the common‐mode suppression within the operating band better than 1.5 dB is achieved. All the results show that the proposed antenna can be widely used in UWB wireless communication systems, medical imaging systems and vehicular radars. © 2016 Wiley Periodicals, Inc. Microwave Opt Technol Lett 59:73–77, 2017

Modular baseband pulse generator for impulse‐radio ultra‐wideband transmitter

A new concept of burst generator architecture dedicated to impulse-radio ultra-wideband wireless communication systems is presented. Bursts are generated by using four elementary baseband pulse generators operating in parallel. Thus, the resulting waveform is the amplitude and phase addition of time-overlapped pulses. The circuit has been implemented in 65 nm CMOS technology under a 1.2 V supply voltage. Simulation results are presented exhibiting a power consumption of 7.24 mW.

Differential‐fed ultrawideband polarization diverstiy antenna with dual notch bands

ABSTRACTA differential‐fed ultrawideband (UWB) polarization diversity antenna with dual band‐notched features is proposed in this letter for the first time. The antenna is composed of a smoothing square slot and two orthogonal differential pairs aiming to achieve polarization diversity operation across the UWB from 2 to 11 GHz. High differential port isolation of less than −40 dB is also obtained. Besides, the embedded C‐shaped slots on the main radiation elements are used to filter 5.5 GHz wireless local area network band and 8 GHz X‐band. A prototype has been manufactured and tested. Results show that the antenna will be promising for the application in UWB wireless communication systems. © 2015 Wiley Periodicals, Inc. Microwave Opt Technol Lett 57:1084–1089, 2015

Uniplanar differentially driven UWB polarisation diversity antenna with band‐notched characteristics

A differentially driven ultra-wideband (UWB) polarisation diversity antenna with dual notch bands is presented for the first time. The antenna consists of a chamfer square slot and two differential pairs being orthogonal to achieve polarisation diversity performance over the UWB. The proposed antenna has a wide impedance bandwidth from 2.75 to more than 11 GHz for differential reflection coefficients less than −10 dB, and a high differential port-to-port isolation of less than −40 dB. Dual band-rejected operation to filter the 3.5 GHz WiMAX and 5.5 GHz WLAN bands is obtained by employing two different methods. All these features make the proposed antenna very suitable for applications in UWB wireless communication systems.