quasi-Yagi Antenna Research Articles

A Scalable and Multidirectional Rectenna System for RF Energy Harvesting

A rectenna system having multidirectional receiving capability and scalable antenna gain is presented for radio frequency (RF) energy harvesting. The technique of ray tracing was implemented to evaluate RF power collected by antennas with different half-power beam widths. The results indicate that different radiation features are suited to distinct scenarios. This further indicates that a scalable and multidirectional radiation characteristic is highly desired for energy-harvesting antennas because the level of ambient energy varies over time and space. Accordingly, a rectenna system is proposed that can scale in array size, antenna gain, direction of reception, and radiation pattern to enhance conversion efficiency and dc outputs. The proposed device is comprised of five rectenna cells. Each cell consists of a quasi-Yagi antenna with variable numbers of directors and one RF-to-dc energy-harvesting circuit. Thus, the proposed system can achieve either uniform coverage with enhanced antenna gain or highly directional characteristics at one/multiple incidence angle(s). A prototype is designed, fabricated, and tested in terms of each component and the entire system. The experimental results indicate that the proposed system can be useful in various scenarios, and it outputs enhanced power as scaling is performed in the direction of reception and antenna gain.

Dual-Wideband Magnetoelectric Dipole Antenna With Director Loaded

In this letter, a dual-band magnetoelectric (ME) dipole antenna with wide operation bands is proposed for WiMAX and WLAN applications. A full-metal rectangular director is loaded right above the ME dipole antenna and it resonates at around 3.6 GHz due to the excitation of the long electric dipole (LE-dipole). Then, the lower operation bandwidth is extended significantly. This added director also allows our antenna to work as a quasi-Yagi antenna at specific frequencies, and thus, the proposed antenna is capable to achieve better unidirectional radiation performance and higher gain. In order to satisfy WLAN communication, a short trapezoid electric dipole is designed beneath the LE-dipole, which maintains the overall antenna dimensions as unchanged. Besides, such design strategy avoids the distortion of the radiation pattern at 5 GHz as well. As for the ground, a hornlike reflector is adopted instead of traditional planar structures. The measured results show that our proposed antenna achieves two wide bandwidths, 2.3–3.7 GHz (46.7%) and 5–6.25 GHz (22.2%), and high stable gain (8.5 ± 0.9 and 9 ± 1 dB) within these two operation bands.

Microfluidically Frequency-Reconfigurable Quasi-Yagi Dipole Antenna.

In this paper, a frequency reconfigurable quasi-Yagi dipole antenna is proposed by leveraging the properties of microfluidic technology. The proposed antenna comprises a metal-printed driven dipole element and three directors. To tune resonant frequencies, microfluidic channels are integrated into the driven element. To maintain a high gain for all the tuned frequencies, microfluidic channels are also integrated into the directors. Therefore, the length of the driven-element as well as directors can be controlled by injecting liquid metal in the microfluidic channels. The proposed antenna has the capability of tuning the frequency by varying the length of the metal-filled channels, while maintaining a high gain for all the tuned frequencies. The proposed antenna’s performance is experimentally demonstrated after fabrication. The injected amount of liquid metal into the microfluidic channels is controlled using programmable pneumatic micropumps. The prototype exhibits continuous tuning of the resonant frequencies from 1.8 GHz to 2.4 GHz; the measured peak gain of the proposed antenna is varied in the range of 8 dBi to 8.5 dBi. Therefore, continuous tuning with high gain is successfully demonstrated using liquid-metal-filled microfluidic channels.

A Differential UWB Quasi-Yagi Antenna with A Reconfigurable Notched Band

Abstract A compact differential ultra-wide band (UWB) planar quasi-Yagi antenna is presented in this paper. The proposed antenna consists of a balanced stepped-impedance microstrip-slotline transition structure, a driver dipole and one parasitic strip. A wide differential-mode (DM) impedance bandwidth covering from 3.8 to 9.5 GHz is realized. Meanwhile, a high and wideband common-mode (CM) suppression can be achieved by employing the balanced stepped-impedance microstrip-slotline transition structure. It is noted that the DM passband is independent from the CM response, which can significantly simplify the design procedure. In addition, a reconfigurable sharp DM notched band from 5.6 to 6.7 GHz is generated by adding one pair of quarter-wavelength varactor-loaded short-circuited stubs adjacent to the microstrip line symmetrically. In order to illustrate the effectiveness of the design, two prototypes of the antennas are designed, fabricated, and measured. A good agreement between the simulated and measured results is observed.

Design and realization of quasi Yagi antenna for indoor application with 3D printing technology

AbstractWith the advances in the extrusion depositing base three‐dimensional (3D) printing technology and decreases in their costs, these technologies are being used in many fields for fast and low cost prototyping means. One of these applications is manufacturing of microwave circuits. Herein, design and realization of quasi Yagi antenna for indoor application with 3D printing technology is presented. First, design of a wide band microstrip quasi Yagi antenna consists of a dipole fed by a coplanar strip line, a rectangular patch, and a ground reflector is studied. The size of the antenna is reduced by using a half bowtie shaped dipole and reflector. The studied microstrip quasi Yagi antenna is aimed to operate within the operation frequency range of 670–3000 MHz. Then for experimental results, the designed antenna is fabricated by using a 3D printer with poly(lactide acid) material. From observing the experiment results it can be concluded that 3D printed antenna has good performance, within the operation band with a good return loss characteristic performance of less than −10 dB and a moderate gain of 3.5–4.6 dBi. As it can be seen, the 3D printer technology is an efficient method for fast and accurate prototyping of antenna design.

Frequency Reconfigurable Quasi-Yagi Antenna with a Novel Balun Loading Four PIN Diodes

AbstractA novel frequency reconfigurable Quasi-Yagi antenna is proposed. The antenna has two dipoles on different layers of the substrate and they are fed by two coplanar striplines. Four PIN diodes, loading inside the coplanar striplines, are used as the switches. By switching the states of the four diodes, the antenna can work in three modes with different working bands around 3.5 GHz (cover the band of WiMAX), 5.2 GHz (cover the band of WLAN) and 7 GHz respectively. In addition, the working bands can be independently tuned by adjusting several parameters of the antenna. A prototype antenna was fabricated and tested. Good agreement between the simulation and the measurement is achieved. The results prove that the antenna can realize frequency reconfiguration effectively while maintaining the pattern characteristic of Yagi antenna at all frequency.

Highly miniaturised semi‐loop meandered dual‐band MIMO antenna system

A novel dual-band two-element directional multiple-input-multiple-output (MIMO) antenna system is presented with 68% miniaturisation, which is achieved using a semi-loop meandered driven element and a small ground plane. The centre frequency of operation is 2 GHz. The antenna system covers two bands: the telemetry L-band 1.27-1.43 GHz and the global system for mobile communications/long-term evolution band 1.8-2.133 GHz. The simulation and measurement results are in good agreement. The proposed antenna system mimics the quasi-Yagi antenna configuration with a measured front-to-back ratio of around 15 dB at 1.35 GHz and 17 dB at 2 GHz, which is achieved without using a large ground plane, extra metallic structures, multiple reflector elements, or any complex technique. A gain of more than 5 dBi is measured for the single element with a total radiation efficiency of around 85% in both bands. The measured isolation of the proposed MIMO antenna is more than 15 dB with <;0.0785 measured envelope correlation coefficient values in both bands.

Compact planar quasi‐Yagi antenna with band‐notched characteristic for WLAN and DSRC for ultra‐wideband applications

A compact planar quasi-Yagi antenna with a wideband microstrip-to-slotline transition and a modified bow-tie driver is designed with an enhanced bandwidth for precise indoor positioning applications. A compact interdigital capacitor loaded loop resonator with a high quality factor is placed inside the ring resonator at the end of the antenna's slot to realise band-notched characteristics over a frequency range of 5.1-6.3 GHz, thus avoiding interference from wireless local area networks (WLANs) and dedicated short-range communications (DSRCs). Measured results show that the proposed antenna obtains a relative impedance bandwidth, determined by the voltage standing wave ratio <;2, higher than 122.6% (3.0-12.5 GHz) and a gain of 4.9-7.8 dBi outside of the stop band.

Prof. Itoh's Contributions to Antennas [Awards

Prof. Tatsuo Itoh is a preeminent researcher, mentor, and educator, whose efforts have influenced many in the field of electromagnetics and microwave engineering. Although Prof. Itoh may be best known for numerical techniques and periodic/metamaterial structures, he has also left his mark in the antenna community. Some of Prof. Itoh's antenna-related works include antennas and arrays that integrate active components such as push–pull power amplifiers and coupled oscillators to enable efficient radiation, spatial power combining, and beamsteering; broadband planar quasi-Yagi antennas that produce highly directive end-fire radiation [S34]–[S35]; uniplanar-compact photonic bandgap (PBG)-enhanced high-gain antennas; retrodirective arrays that can reradiate an incoming signal toward the source without a priori knowledge of the arrival direction; and metamaterial antennas that support unconventional radiation characteristics such as broad spatial-angle frequency scanning and negative/zeroth-order mode radiations.

Indented Antenna Arrays for High Isolation: The Growing Interest in Simultaneous-Transmit-and-Receive-Based Full-Duplex Communication Systems

In full-duplex communication systems, reflections of transmitted waves as a result of the antenna mismatch may leak into the receiver and create strong on-site interferences. Such reflections cannot be suppressed by conventional frontend isolation techniques even with ideal circulators. Indented antenna arrays are thus proposed to destructively combine the reflection from each antenna element and prevent them from negatively impacting the receiver sensitivity. The essential idea is to break the symmetry between the transmitting and receiving paths by using an antenna aperture that is curved by indenting the antenna elements. Because of this asymmetry, all of the elements contribute to the wave transmission and reception in phase, whereas the reflections from those elements are out of phase and cancel each other out. With indented antenna configurations, broadband isolation between the transmitting and receiving paths can be achieved for both monostatic and bistatic antenna settings. The improvement is obtained without sacrificing antenna radiation patterns or polarizations. Measured results with a four-element indented quasi-Yagi antenna array operating from 3.2 to 3.4 GHz are presented. The results have demonstrated a 13-dB improvement on the antenna return loss of a single array, a 15-dB transmit/receive isolation improvement in a monostatic array, including circulators, and a 20-dB transmit/receive isolation improvement for a bistatic array without using circulators.

Printed Quasi-Yagi Antennas Using Double Dipoles and Stub-Loaded Technique for Multi-Band and Broadband Applications

Double dipoles on a single-layer substrate are utilized to construct a triple-mode printed quasi-Yagi antenna for the multi-band and broadband antenna applications. A stub-loaded dipole generating two resonant modes (i.e., lower dual-mode dipole) is allocated on the underside of a simple dipole (i.e., upper single-mode dipole) introducing the third resonant mode. Using these three resonant modes, three compact printed quasi-Yagi antennas, i.e., tri-band, dual-band, and broadband printed quasi-Yagi antennas, are designed with the same antenna prototype but different parameter values. Seen from the measured results, all of these three antennas have good unidirectional radiations, high radiation efficiencies, and low cross-polarization levels at the operating frequencies within the impedance bandwidths.

Compact, wideband‐printed quasi‐Yagi antenna using spiral metamaterial resonators

A novel structure for size reduction and bandwidth enhancement of quasi-Yagi antenna using spiral resonator (SR) metamaterials is presented. The basic resonance is produced through excitation of simple quasi-Yagi antenna elements through a microstrip feedline while parasitic SR metamaterials augment bandwidth. The antenna is designed on an glass-reinforced epoxy laminate sheets (FR4) substrate with a dielectric constant of 4.4 and a thickness of 1.6 mm. Compared to original printed quasi-Yagi antennas, the size of the proposed quasi-Yagi antenna is reduced by ∼53%. Simulation results show that the proposed antenna has the impedance characteristics with a frequency bandwidth of 1.43–3.97 GHz (94%) for return loss more than 10 dB and a gain of 3.4–5.2 dBi in the corresponding frequency range. The designed antenna presents an end-fire radiation with a front-to-back ratio >10 dB. The antenna is fabricated, and measurement results demonstrate compactness and wide bandwidth of the antenna.

Dual‐band and dual‐polarized antenna with endfire radiation

A novel dual-band endfire antenna with dual polarisation is proposed. The antenna is composed of a shorted metal cavity which functions as a magnetic dipole, a bowtie-shaped electric dipole and an I-shaped resonator (ISR) array. Owing to the combination of complementary dipoles, circularly polarised (CP) electromagnetic waves are generated in the endfire direction at the lower band. A quasi-Yagi antenna structure is adopted to attain broadband linearly polarised (LP) radiation in the upper band. In addition, an ISR structure is loaded to improve the gain in endfire direction. The measured 10-dB impedance bandwidths are 3.93% at the lower band and 29.45% at the upper band, respectively, and the 3-dB axial-ratio bandwidth of 150 MHz (5.76 to 5.91 GHz) is observed in the CP band. Besides, the ISR loaded antenna demonstrates 2-3.5 dB gain improvement over the operational band. This antenna could find applications in radio-frequency identification and indoor positioning systems.

A Compact Ultra-Wideband Planar Printed Bow-Tie Quasi-Yagi Antenna with Rhombus Director and Tapered CPS Connection Structure

ABSTRACTA compact ultra-wideband (UWB) planar printed bow-tie quasi-Yagi antenna is proposed and experimentally studied in this paper. It is composed of three wideband configurations: micro-strip-line to slot-line transition structure with a shorting vias (balun), a pair of bow-tie driver, and rhombus director, which aims at breaking the bandwidth limitation of the conventional micro-strip (MS) quasi-Yagi antenna. To further improve the impedance matching, the tapered co-planar strip-line is adopted between the bow-tie driver and the balun as bridge. The overall size of the proposed antenna is only 30 mm × 27 mm. A prototype UWB quasi-Yagi antenna is fabricated and measured to verify the validity of this design. The measured impedance bandwidth, defined by −10 dB reflection coefficient, can reach an operating bandwidth of 101% from 3.62 to 11 GHz, over which the antenna exhibits excellent end-fire radiation with a front-to-back ratio of greater than 19 dB and a moderate gain of better than 3.81 dBi. In contrast to the conventional micro-strip quasi-Yagi antenna design, our proposed antenna features a smaller size and wider −10 dB reflection coefficient bandwidth.

A CPW-fed broadband quasi-Yagi antenna with low cross-polarization performance

This paper presents a uniplanar quasi-Yagi antenna with the coplanar waveguide feed line. A novel driver dipole is proposed to expand the working frequency band of the antenna. Due to the unique driver dipole, the proposed quasi-Yagi antenna can work from 3.75 to 10.4GHz with good end-fire radiation gain (>4dBi) and low cross-polarization performances. To verify the design, a prototype antenna is fabricated and measured. The experimental results are in accordance with the simulation results very well.

Dielectric Loaded Endfire Antennas Using Standard Silicon Technology

This paper presents two endfire on-chip antennas (OCAs) at 140 and 320 GHz using a standard 0.13- $\mu \text{m}$ SiGeBiCMOS technology; quasi-Yagi antenna concept is used with loaded dielectric. In order to eliminate the influence of the low-resistivity silicon substrate, the substrate thickness is chosen as $\sim 84~\mu \text{m}$ (for 140 GHz), and the antenna is mounted on the edge of a metal supporter with the front part ungrounded. The loaded dielectric is designed using the silicon and silicon dioxide (SiO2) layers to improve the gain. The antenna shows the measured impedance bandwidth of >45% at 140 GHz, with the peak gain of 4.1 dBi, and the simulated peak radiation efficiency of 83%. A $1 \times 2$ array at 140 GHz is also designed and implemented; the corresponding measured impedance bandwidth, peak gain, and simulated radiation efficiency are >36%, 7 dBi, and 72%, respectively. With the proposed structure, the OCA at 320 GHz is also designed and fabricated with the substrate thickness of $\sim 34~\mu \text{m}$ . The measured gain of 3.9 dBi and the simulated radiation efficiency of 80% are achieved at 320 GHz, respectively.

Pattern Reconfigurable Antenna Based on Morphing Bistable Composite Laminates

In this paper, a novel pattern reconfigurable antenna based on morphing bistable composite laminates is presented. The bistable asymmetric glass-fiber reinforced polymer (GFRP) composite laminates have two stable configurations with curvatures of opposite signs. The antenna pattern is reconfigured by transforming the configuration of the bistable GFRP laminate which acts as the substrate of the antenna. The coplanar waveguide transmission lines feeding technique is used for the microstrip quasi-Yagi antenna. A prototype of the proposed antenna is fabricated using a semi-automatic screen printer and an autoclave. The transformation between the two stable states of the proposed antenna using Ni/Ti shape memory alloy springs is investigated experimentally. The out-of-plane displacements, reflection coefficients and radiation patterns for the two stable configurations of the antenna are measured, which agree well with the simulated results. The main beam direction is 89° and 59° for the two stable configurations, respectively. In addition, the influences of various bending radii on the radiation patterns are investigated to gain a thorough understanding of the reconfigurable mechanism of the proposed antenna. Finally, a two-element array of such an antenna is presented and measured. The proposed antenna provides a potential application in multifunctional, conformal, morphing, and integrated structures.

Design of tri-band double-dipole quasi-yagi antenna using dual co-directional SRRs

Design of tri-band double-dipole quasi-yagi antenna using dual co-directional SRRs

A novel wideband planar quasi-yagi antenna loading with parasitical patches and multiple reflectors

A novel wideband planar quasi-yagi antenna loading with parasitical patches and multiple reflectors

Low-Profile Helical Quasi-Yagi Antenna Array With Multibeams at the Endfire Direction

This letter presents a novel helical quasi-Yagi antenna array with low profile and multibeams at the endfire direction. First, a planar normal-mode helical quasi-Yagi antenna with top-hat loading for low profile is designed to achieve endfire radiation. It is mounted on a conducting plane, consisting of a top-loaded folded helix as the driven element and three top-loaded unfolded helices as parasitic elements. A broadband can be achieved by controlling the resonance difference between the driven and parasitic elements. Second, a microstrip beamforming network based on Butler matrix is designed to feed a 1 × 4 helical quasi-Yagi array. The proposed antenna array is fabricated and tested. Measured results show that three endfire beams at ϕ = 90°, (90 ± 47)° are obtained while the antenna has a very low profile of 0.054 λ at its center frequency, showing that the antenna may be useful in many airborne applications such as unmanned aerial vehicles.