Bent Antenna Research Articles

A design of dual band wearable MIMO antenna using Organza fabric for medical applications

A novel wearable dual-band MIMO antenna featuring good conformal characteristics under bending conditions is presented. The dielectric part of the antenna is built on a flexible substrate using layered lightweight plain weave fabric Organza with a relative permittivity of 1.63 to achieve a low-light and flabby textile. A defected ground structure (DGS) is employed for improving diverse parameters such as narrow bandwidth and resonant adjusting. The DGS part of the antenna is a resonant slot in the ground layer, placed directly under the patches. The electromagnetic energy is transmitted to the radiating slots using a recessed microstrip line feed along with semi co-planar waveguide (CPW) structure with defective ground metal in the bottom layer. It is worthwhile to point out that using the highly flexible Organza fabric with the ability to change the substrate thickness provided acceptable antenna characteristics under the bending condition in different directions. To validate the design, a prototype antenna is fabricated and experimentally investigated. The effect of substrate thickness on antenna performance is investigated by changing the number of Organza layers in both simulation and experiments. A good agreement is attained between the simulation results and the measurement results. The antenna properties such as scattering parameters, radiation patterns, and SAR values are investigated under bending conditions. Results show that the maximum measured gain is 7.8 dB at 2.4 GHz and 7.3 dB at 5 GHz. The simulated specific absorption rate (SAR) values are less than 0.336 W/Kg and 0.468 W/Kg at 2.4 GHz and 5 GHz for 1 g human body tissue, respectively. The SAR values for the bent antenna are less than 0.302 W/Kg and 0.458 W/Kg at 2.4 GHz and 5 GHz for 1 g human body tissue, respectively.

2D Titanium carbide printed flexible ultrawideband monopole antenna for wireless communications

Flexible titanium carbide (Ti3C2) antenna offers a breakthrough in the penetration of information communications for the spread of Internet of Things (IoT) applications. Current configurations are constrained to multi-layer complicated designs due to the limited conformal integration of the dielectric substrate and additive-free Ti3C2 inks. Here, we report the flexible ultrawideband Ti3C2 monopole antenna by combining strategies of interfacial modification and advanced extrusion printing technology. The polydopamine, as molecular glue nano-binder, contributes the tight adhesion interactions between Ti3C2 film and commercial circuit boards for high spatial uniformity and mechanical flexibility. The bandwidth and center frequency of Ti3C2 antenna can be well maintained and the gain differences fluctuate within ±0.2 dBi at the low frequency range after the bent antenna returns to the flat state, which conquers the traditional inelastic Cu antenna. It also achieves the demo instance for the fluent and stable real-time wireless transmission in bending states.

Compact Bent-Corner Orthogonal Beam Switching Antenna Module for 5G Mobile Devices

Typically, users engage with smartphones in either single-hand or dual-hand mode. To design antennas that operate at 28 GHz and have high pattern integrity for both modes of operation, an orthogonal beam switching module is required as a single phased-arrays would fail. First, a corner bent corporate fed array operating at 28 GHz is proposed, which has a forward gain of 8.5 dBi and a high-front-to-back ratio of 20 dB. Second, a corner bent printed Yagi antenna that also operates in the 28 GHz band is proposed. Both the corner bent antennas are compatible with the panel edge of commercial smartphones. The radiation from both antennas is mostly directed away from the user. A corner bent co-polarized orthogonal beam switching module is presented and characterized. The antenna module also has a shared ground, making it a potential candidate for future 5G smartphones. Detailed results are presented with adequate justification.

Dual Band Switched Beam Textile Antenna for 5G Wireless Communications

This paper presents the single element dual band switched beam textile antenna. The antenna can operate at frequencies of 0.7 and 2.6 GHz using for 5G wireless communication applications. Textile fabric is considered to be used for substrate layer at the parts of a microstrip antenna for wireless body area network. The beam pattern of antenna can be switched into two directions by changing the position of shorted-circuit points at each edge of antenna. The main beam direction is 45°/225° when corner A is shorted while it steers at 135°/315° when corner B is shorted circuit. The advantage of the proposed antenna is the decrease of the problems like interference, light weight, flexibility and ability to switch beam easily. In addition, the results of the fabricated antenna are compared with the simulated ones. Moreover, the antenna is bent with curvature radius of 6 mm in forward direction. The effects of the bent antenna are studied. The results can confirm that radiation patterns of the bending antenna can be pointed into two directions when changing the positions of shorted circuit. Therefore, the proposed antenna can switch beam patterns, it is flexible, and it can operate at dual-band frequency on textile.

MIMO CPW-Fed Bent Antenna Based USB Dongle for ECMA-368 WPANs

A multiple-input-multiple-output (MIMO) ultra-wideband (UWB ) printed bent antenna, suitable for MB-OFDM ECMA-368 system integration with the wireless universal serial-bus (WUSB) dongle is proposed. The antenna consists of two antenna elements with an overall area of 18 X 53 mm2. Each antenna element is a simple modified folded-monopole fed by a coplanar waveguide (CPW). The design process of proposed MIMO UWB CPW-fed bent antenna configuration is presented in four simple steps. Experimental results show that the proposed design has a good impedance bandwidth in the range of 2.95–18.55 GHz with 147.2% fractional bandwidth (FBW). Moreover, the proposed antenna enjoys, low envelope correlation coefficient (ECC), good diversity gain (DG), low total active reflection coefficient (TARC) and omnidirectional radiation patterns. The bit error rate (BER) of the overall MB-OFDM ECMA-368 system with the existence of the proposed MIMO UWB CPW-fed bent antenna is evaluated in more realistic transmission channel scenario by using the extracted transmitting and receiving UWB antennas transfer functions.

An Ultra-Wideband Antenna With Low Dispersion for Ground Penetrating Radar System

An Ultra-wideband Antenna with funnel-shaped slots and rectangle copper sheets loaded was proposed for ground penetrating radar applications covering the frequency range from 250 MHz to 780 MHz. The performances of the proposed antenna were modeled and optimized by using finite difference time domain methods and measured in both time and frequency domains. The proposed antenna had a bandwidth of 102.9% with voltage standing-wave ratio (VSWR) < 2 and a pick gain over 3 dBi, even when the antenna was bent according to the shape of antenna carrier. In addition, a reconfiguration antenna array with switching matrix, which could be loaded up to 12 antennas, was proposed, where the scanning strategy could be programmed according to the requirements. On this basis, the VSWR of antenna array with and without switching matrix were compared, and the performances of bent and non-bent antenna were also compared in the far-field region. For the radiation pattern, the back-lobe level of bent antennas in E-plane was much lower than non-bent antennas, and the main-lobe of bent antennas in H-plane were rotated. For the peak realized gain, although the antenna gain decreases with increasing frequency, the rate of decline of bent antenna gain is significantly less than that of non-bent antenna gain. Finally, the fabricated antennas could be loaded on a SFCW-GPR system for detecting the depth of cable wells under the road.

A novel reverse design method of tag antenna based on image analysis

Since the working efficiency of the entire radio frequency identification system depends on the performance of the radio frequency identification tag antenna, the research and design of the tag antenna have received attention, especially for radio frequency identification tags applied to special scenes. We mainly studied the effect of antenna bending on the performance of ultra-high frequency radio frequency identification systems, and combined the bent antenna with the impedance matching loop to achieve impedance matching between the chip and the antenna in the ultra-high frequency band. We analyzed the variation of tag antenna performance with antenna parameters by the simulation software High Frequency Structure Simulator (HFSS). At the same time, we propose a novel antenna reverse design method. Through the analysis of the antenna-specific absorption rate image, the antenna performance intensity is visually reflected. According to the image analysis result, the antenna parameters are corrected to improve the antenna matching performance. This design method is simpler and faster than other methods.

A flexible wide band single fed slot antenna with circular polarizing rotated elliptical ground and impulse response

AbstractIn this paper, a flexible single fed planar circular polarized slot antenna is proposed for Internet of Things wideband applications. The antenna flexibility is achieved by employing a mechanically bendable liquid crystalline polymer substrate. The overall antenna volume is 50 mm × 42 mm × 0.1 mm. The antenna design uses 45° rotated elliptical ground structure for generating circular polarized radiation over wideband spectrum. Two parametrical analyses targeting the slot ground are introduced in order to achieve the most efficient design. The final antenna design demonstrates a good matching in terms of reflection coefficient (&lt;−10 dB), semi-omnidirectional radiation patterns, average gain of 4 dB, and &lt;3 dB axial ratio over entire frequency band of operation. All antenna parameters are studied in both straight and bent antenna setup scenarios. Good agreement between simulation and measurement results of the antenna parameters are achieved. For both straight and bent antenna scenarios, the antenna receiving functionality in time domain is confirmed by retrieving highly correlated impulse responses.

CPW Fed Wideband Corner Bent Antenna for 5G Mobile Terminals

A co-planar waveguide fed slot antenna element with 34% impedance bandwidth and 2-3 dBi broadside gain is proposed. The corner bent topology of the element is investigated for reduced physical footprint and easier integration with the mobile terminals operating in the 28-GHz band. The front-to-back ratio of the corner bent antenna is 1 dB in the xy plane, which indicates a high specific absorption rate. A compact wideband reflector is proposed which has transmission of less than -25 dB and a linear phase ±90° in the 27-33-GHz bandwidth. The wideband reflector is integrated with the corner bent antenna at 0.135λ offset from the radiating aperture. The corner bent antenna integrated with the reflector operates in the 27-33-GHz band, with a front-to-back ratio of more than 14 dB across the band and a forward gain of 6-7.2 dBi. The radiation patterns are stable for 20% bandwidth. The simulated and measured results are presented.

Multi-Band Hybrid Mobile Phone Antenna Based on Electromagnetic Coupling

This research presents a multi-band hybrid mobile phone antenna based on electromagnetic coupling, which can be applied to mobile handheld devices, occupying a small board space of 39.7mm×15.6mm on the system circuit board. By adding resonant and coupled branch instead of multi-feed on the traditional bent antenna, this design provides four wide operating bands of 0.772—0.998 GHz, 1.540—1.600 GHz, 1.680—2.270 GHz and 2.300—2.690 GHz with the hybrid feature of planar inverted-F antenna (PIFA), L-shape, U-shape and S-shape structures, which cover nine-band, i.e., GSM850, GSM900, GPS1575, DCS1800, PCS1900, IMT200, LTE2300, LTE2600 and Blue Tooth/Wi-Fi. Ansoft software HFSS is used in this research to make the antenna performance better and the operating principle of the proposed antenna is described in detail. Result of simulation reveals that the maximum gains of these four wide bands are 2.20, −0.99, 4.01 and 4.05 dBi, respectively. Moreover, this research also tests the return loss (S11) of the fabricated antenna with the vector network analyzer and the result is in accordance with the simulation result on the whole. There are four wide resonant frequencies which cover nine-band of wireless wide area network (WWAN), wireless local area network (WLAN) and long term evolution (LTE), when the available bandwidth is better than 6 dBi return loss.

Comparative Study between Planar and Bent Antenna Characterization

Smaller designs of antenna usually implemented on Wi-Fi modules or navigation system devices which requires smaller bandwidth such as Planar Antenna. There are some antenna application requires bent antenna such as wearable UWB antenna but the substrate used will have some defects after bending and crumpling from time to time. What if the planar antenna is designed that it can be bent and the bending affects the impedance matching and shift in resonant frequency? So, this research aims to achieve the limitation of the planar antenna to be bent at certain angle and given frequency range (1-8 GHz). The planar antenna is designed in the Computer Simulation Technology (CST) Software and the proposed antenna is then bend in the simulation software. The analysis of comparative evaluation for both planar and bent antenna is carried out on different characteristics such as evaluation between S-Parameters &amp; Frequency and evaluation between Voltage Standing Wavelength Ratio (VSWR) &amp; Frequency. The behaviour of radiation pattern for both antennas can also be obtained in the CST simulation.

DESIGN AND SIMULATION OF FULLY PRINTABLE CONFORMAL ANTENNAS WITH BST/POLYMER COMPOSITE BASED PHASE SHIFTERS

A fully printable and conformal antenna array on a flexible substrate with a new Left- Handed Transmission Line (LHTL) phase shifter based on a tunable Barium Strontium Titanate (BST)/polymer composite is proposed and computationally studied for radiation pattern correction and beam steering applications. First, the subject 1 × 4 rectangular patch antenna array is configured as a curved conformal antenna, with both convex and concave bending profiles, and the effects of bending on the performance are analyzed. The maximum gain of the simulated array is reduced from the flat case level by 34.4% and 34.5% for convex and concave bending, respectively. A phase compensation technique utilizing the LHTL phase shifters with a coplanar design is used to improve the degraded radiation patterns of the conformal antennas. Simulations indicate that the gain of the bent antenna array can be improved by 63.8% and 68% for convex and concave bending, respectively. For the beam steering application, the proposed phase shifters with a microstrip design are used to steer the radiation beam of the antenna array, in planar configuration, to both negative and positive scan angles, thus realizing a phased array antenna.

Radiation characteristics of a flexible micro-electro-mechanical system antenna on a liquid crystal polymer substrate

Liquid crystal polymers are flexible polymer materials that can be used as a substrate in flexible micro-electro-mechanical system antennas. Flexible liquid crystal polymer substrate antennae can satisfy the demand for wearable and conformal applications. In this study, a flexible micro-electro-mechanical system antenna based on a liquid crystal polymer substrate is presented with a central frequency of 14 GHz. The relationships between the electrical parameters and the curvature K are obtained in order to investigate the radiation characteristics of the bent antenna with 0.04 ≤ K ≤ 0.2. The analysis results show that the antenna with a liquid crystal polymer substrate demonstrates a good radiation performance in its bent state with 0.04 ≤ K ≤ 0.2, which provides a viable option for wearable and conformal applications.

Design of an ultrawideband conformal metal antenna

ABSTRACTIn this article, a novel design of volcano smoke antenna is proposed as an ultrawideband (UWB) conformal antenna. The radiating element and CPW feed line are in the same plane that makes the antenna completely planar. The proposed planar metal antenna is bent on a cylindrical surface, and the characteristics of the antenna for different bent conditions are studied. This study shows no significant change of reflection coefficient and radiation pattern characteristics of the bent antenna compared to that of flat position. The impedance bandwidth for S11 &lt; −10 dB of the bent antenna covers the UWB (3.1–10.6 GHz). Variation of absolute gain and group delay of the antenna under flat and bent conditions are shown in this article. The measured reflection coefficient agrees with the simulated results. © 2014 Wiley Periodicals, Inc. Microwave Opt Technol Lett 56:430–434, 2014

Flexible Antenna의 Bending 특성

본 논문에서는 Flexible-PCB에 제작된 안테나를 구부렸을 때의 특성 변화를 살펴보았다. Polyimide로 이루어진 Flexible-PCB는 유전율 3.5, 두께 0.125 mm를 가진다. 제안된 안테나는 Bluetooth 대역을 만족하는 기본적인 장방형 루프 안테나와 입력부에 Inverted-L 형태의 스터브를 추가한 안테나이다. 제안된 두 가지 안테나 모델에 대하여 8가지 조건의 bending 변화를 통해 bending 정도에 따른 입력 정합 특성과 방사 형태를 비교하였다. In this paper, we studied characteristics of the bent antenna febricated on Flexible-PCB. Flexible-PCB consisting of a polyimide has dielectric constant 3.5, thickness 0.125 mm. Proposed antennas which operates at Bluetooth band are a rectangular loop antenna and a loop antenna with inverted-L type stub. We compared the input matching and radiation characteristics of the proposed antennas under eight kinds of bending conditions.

Performance of Printed Polymer-Based RFID Antenna on Curvilinear Surface

The performance of flexible printed RFID tags affixed onto cylindrical containers is dependent on the inductive behavior of the bent antenna on the tag. Conductive polymeric coil antennas were screen printed onto flexible substrates, and the coil resistances, the inductances, and the S-parameters of the antenna coils were measured and analyzed. The RFID dies were mounted onto the antenna coils and the read ranges were characterized as a function of curvature. The results show that the coil inductance decreased slowly with increasing curvature, and the maximum read range of the tags was markedly reduced with the curvature. The decrease in the coil inductance and the maximum read range were hypothesized to vary with the projected bent coil area instead of the geometric coil area. Experimental results confirmed that the maximum read range of an RFID tag affixed on a curvilinear surface can be predicted by the classical inductive coupling model with the bent projected coil area. On the basis of the experimental and analytical results, a reading reliability factor of two is proposed as a design parameter for flexible RFID tags.

Characteristics of bent wire antennas

The input (VSWR) and the radiation (pattern and gain) characteristics of two classes of bent wire antennas e.g. the sinusoidal and the meander were measured experimentally as a function of their shortening ratios (SR's). The design variables for these configurations were defined and then correlated with the antenna characteristics. The results of the input characteristics show that for both types of antennas the bandwidth becomes narrower as the shortening ratio increases. For a shortening ratio larger than 30%, VSWR 2.0. However, it was found that for the same shortening ratio the sinusoidal antenna has better VSWR frequency characteristics than the meander. Measured radiation patterns (both H-plane and E-plane) of both classes of antennas show that these are similar to the pattern of a straight quarter-wave monopole. The half-power beam width's (HPBW's) of these bent antennas are somewhat wider (42° -44° ) than that of a straight quarter-wave monopole (39°). The gain of the bent antenna was found to be ...

Radiation Characteristics of Bent-Wire Antennas

A mathematical model, which predicts the far-field power pattern of a wire antenna bent in one plane, is developed, and the classical approximation of a sinusoidal current distribution along the arc length is employed, neglecting all end and mutual coupling effects. General expressions for the complex Poynting vector, electric- and magnetic-field intensities are also derived in terms of the retarded vector potential. Although the theory for parabolically-bent antennas compares favorably with experiment, it is shown that the agreement is more favorable when the current distribution is computed by the method of moments. In contrast to the figure-eight θ-plane pattern of the conventional straight dipole, the circularly and parabolically bent antennas operating at the first resonance are shown to have radiation patterns approaching omnidirection as the bending curvature is optimized, thus lending themselves to use as replacements for many common dipole applications for gain standards, field probing, reflector feeds, as well as mobile and broadcast antennas.

Directional Properties of Wireless Receiving Aerials

Equations have been given by Moullin to determine the current in a receiving antenna in wireless telegraphy and they have been discussed and extended by Colebrooke, who in particular considered the reception of a plane polarised wave with its electric vector vertical by an antenna which is partly vertical and partly horizontal. His result shows that the intensity of the received signal is independent of the orientation of the receiver. In practice, however, the incident wave front is not vertical, its tilt depending on the wave length and on the resistance of the earth, as shown by Zenneck, and the purpose of this paper is to investigate the effect of the orientation of a bent antenna in the reception of this type of wave. An approximate theory of the Beverage antenna is obtained by the same method.

Researches in Radio-Telegraphy 1

II. IN a previous discourse explanations were given of the property of a closed or partly closed antenna of radiating more in some directions than others, and the action of Marconi's bent antenna was described. Two other inventors, Messrs. Bellini and Tosi, have taken advantage of s this fact to construct antennæ of a very interesting character. They erect an antenna consisting of two wires, each bent into a triangular form, the top ends nearly meeting, the planes of these triangles being at right angles to one another, and both of them vertical. The nearly closed antenna circuits are then inductively coupled with a condenser circuit, which is capable of being swivelled round in various directions. If the said condenser circuit is placed in such a position as to be coupled with one of the triangular antennæ it will cause the maximum radiation to take place in the plane of that antenna, but none at all at right angles to it. If it is coupled with the other antenna it will cause radiation to take place to a maximum degree in the plane of that second antenna. If, however, the oscillatory circuit is placed in an intermediate position, so as to act inductively upon both the nearly closed triangular antennæ, then it can be shown, both mathematically and experimentally, that the radiation of the combined system is a maximum in the direction of the plane of the oscillatory circuit which is coupled with the antenna. Hence, with such a combined antenna, we have it in our power to create radiation most strongly in one direction, although not entirely suppressed in all other directions. By combining together, however, a single vertical antenna with two nearly closed circuit antennae at right angles to one another, Messrs. Bellini and Tosi have constructed a complex antenna which has the property of producing radiation almost entirely limited to one-half the circumjacent space (Fig. 13)., It therefore corresponds to a certain extent in effect to the optical apparatus of a lighthouse, with catoptric or dioptric apparatus, which projects the light from the lamp largely in one direction. It is not yet possible to make with electric radiation of long wave-length that which corresponds precisely with a, beam of light wholly concentrated along a certain cone or cylinder, but it is possible, by the use of a complex antenna as described, greatly to limit the diffusion of the radiation. Since radiating and absorbing power, go hand in hand, it is obvious that such a directive antenna also enables the position of a sending station to be located. Messrs. Bellini and Tosi have accordingly applied their methods in the construction of a radiogoniometer and receiving antenna, by means of which they can locate the direction of the sending station without moving the antenna, but merely by turning round a secondary circuit into a position in which the maximum sound is heard in a telephone connected with the receiver. By the kindness of Captain Tosi am able to exhibit to you their ingenious apparatus Fig. 14).