Yagi Antenna Research Articles

A compact directional microstrip antenna with wide bandwidth, high gain, and high front‐to‐back ratio

AbstractA compact directional microstrip patch antenna is presented. The antenna shows excellent properties, such as vertical polarization, wide bandwidth, high gain, and high front‐to‐back (F/B) ratio. It consists of a main patch and a coupled patch. The two parts are connected with a narrow microstrip line. The proposed microstrip patch antenna can be considered as a Yagi antenna, in which the main patch and the coupled patch serve as the driven element and the director, respectively. With the dual‐mode property of the antenna, it exhibits a wide bandwidth inherently. With a coupled patch directly loading on the main patch as a director, the antenna has its beam pointing in the forward quadrant space. A prototype is fabricated and measured. Measured results show that the proposed microstrip antenna with a compact size provides a wide impedance bandwidth (|S11| < −10 dB) of 11%, and a wide radiation bandwidth of 8.4% in which the gain ranges from 8.35 to 10.01 dBi and the F/B ratio is higher than 15 dB.

An Improved Antenna Scattering Model: An equivalent model based on the reciprocity theorem

The Thevenin and Norton equivalent models of a receiving antenna cannot be used to calculate the antenna's scattered power because they are too simplistic. Based on the reciprocity theorem, a more elaborate equivalent model, consisting of a passive distributed transformer, is proposed for wire antennas in both the transmit and receive modes. The model parameters are derived from the antenna's transfer admittance parameters, the latter obtained under short circuit loading conditions in transmit mode only. A method is then applied to determine the new admittance parameters when the antenna is perturbed by an arbitrary load, which allows the receive-mode current distribution on the antenna to be calculated. Once the receive-mode current is known, scattered power can be calculated with a formula that avoids integration over the far-field sphere. The method has been applied to o a l/2-dipole, l-dipole, and three-element Yagi antenna for resistive loads spanning up to nine decades. Calculated scattered-power values are shown to agree almost perfectly with values obtained using a commercial simulator, thus demonstrating that it is possible to calculate scattered power based on the characterization of the antenna in transmit mode only. Results indicate that the aperture efficiency of a dipole antenna can exceed 50% when it is connected to a mismatched load. Finally, a newly defined transducer efficiency is presented, which can be used to choose an optimum load to obtain the best compromise between the aperture and scattering areas.

Miniaturisation of high‐frequency SURFACE wave radar transmitting antenna

Antennas operating in the high-frequency (HF) bands are generally relatively large in size, which severely limits the application of the antennas. Therefore, miniaturisation of the antenna is necessary. Here, a dual-folded structure Yagi antenna is designed for HF surface wave radar (SWR). Genetic algorithm is employed to optimise and balance the antenna size and performance. At the same operating frequency, the optimised antenna size is much smaller than the traditional Yagi antenna size and can meet the performance requirements of HF surface wave radar transmitting antenna.

A dual‐band high‐gain quasi‐Yagi antenna with split‐ring resonators for radio frequency energy harvesting

AbstractThis article presents a quasi‐Yagi antenna operating with high gain at two frequency bands. Compared with a conventional Yagi antenna, the proposed antenna is designed by integrating a pair of printed split‐ring resonators (SRRs) into the antenna layout. The SRRs introduce a new resonant frequency band and the antenna gain remains high at both the bands. The simulated and measured results show that the antenna is well matched while the antenna gain is 6 and 5.80 dBi at the GSM1800 and ISM2450 bands, respectively. The proposed antenna is compact and efficient and achieves high gain so that it could be successfully used in various wireless communication and radio frequency energy harvesting applications.

Design, analysis and verification of integrated horn array for fast evaluation of probe‐fed antenna measurement setup

Several advanced measurement setups are built up to characterise millimetre-wave (mmWave) antennas fed by microelectronic probes. To evaluate these setups themselves, two or more high-cost antenna samples are conventionally required for several time-consuming calibrations. A low-cost horn array for fast evaluation is proposed, theoretically analysed, and experimentally validated. This horn array simultaneously radiates at end-fire and broad side, and therefore can be used to replace two standalone samples such as patch and Yagi antennas. Moreover, this horn array features rippled pattern with a precisely-controllable series of nulls for sensitivity measurement and straightforward comparison for evaluation. By using the substrate integrated waveguide structure, a mmWave horn array is fabricated in a single-layer printed circuit board to feature easy fabrication and low cost. Good agreement between simulation and measurement shows that, the proposed horn array significantly facilitate a fast and low-cost evaluation of the probe-fed antenna measurement setup.

A novel microstrip Yagi antenna with an improved end‐fire radiation pattern under operation of the TM 20 mode

In this article, a novel microstrip Yagi antenna under operation of the TM20 mode is proposed to obtain an enhanced end-fire radiation pattern. First, a two-element microstrip Yagi antenna is theoretically analyzed under different dimensions of the parasitic element. The results demonstrate that the parasitic element can act as either a reflector or director when its size is smaller or larger than the size of the driven patch, respectively. After that, the equivalent magnetic currents and electric fields of the two-element antenna are formed to provide physical insight into the working principle and radiation performance of the antenna. With these arrangements, an array of four patch elements including one driver, one director, and two reflectors are selected for the antenna design. Unlike the traditional microstrip Yagi operating with the TM10 mode, all the patch elements involved in this design resonate with the TM20 mode, thus effectively enhancing the tilted beam angle toward the desired end-fire direction on an infinite ground. Finally, the proposed antenna is designed, fabricated and tested. The measured results show that its impedance bandwidth is maintained at approximately 3.3%, ranging from 4.76 to 4.92 GHz. Most importantly, the maximum deviation angle of the antenna is significantly improved to approximately 58° from the broadside direction at the center frequency (4.84 GHz), while maintaining a low profile and compact size.

A Microstrip Yagi Antenna With an Enlarged Beam Tilt Angle via a Slot-Loaded Patch Reflector and Pin-Loaded Patch Directors

In this letter, a microstrip Yagi antenna with a resonating patch driver, one slot-loaded patch reflector, and two pin-loaded patch directors is proposed. Different from all the reported counterpart antennas, the lengths and widths of all the patch elements involved herein are set to be the same, and a parasitic patch reflector and patch directors are realized by loading the slot and shorting pins on the patches, respectively. For a square patch, its resonance frequency can be reduced by etching out a slot, acquiring a reflective function. However, its resonance frequency can be increased by adding a pair of shorting pins underneath the patch, thus acquiring a directive function. By placing these two types of parasitic patches in the two sides of the driving patch radiator, an alternative microstrip Yagi antenna can be constructed to achieve a quasi-endfire radiation pattern with an enlarged beam tilt angle. A prototype operating at 5 GHz is finally fabricated and tested. The measured results achieve an impedance bandwidth of 8%. In addition, the maximum deviation angle reaches approximately 56° from the broad side, and its 3 dB beamwidth in the xoy plane exceeds 62°.

Alternative Method for Obtaining Antenna Current Green’s Function Based on Infinitesimal Dipole Modeling

The antenna current Green’s function (ACGF) can be used to consider the mutual coupling effect between multiple arrayed antennas. To obtain the ACGF of antennas, numerical simulations such as moment method (MoM) are mainly used. However, these numerical simulations require large memory and it is time consuming to obtain a solution. The computer-aided design (CAD) model for the numerical simulation should be accurately designed. Therefore, we propose an alternative method for obtaining the ACGF based on infinitesimal dipole modeling (IDM). The IDM is a technique to model antennas with a distribution of theoretically expressed dipoles. The infinitesimal dipoles have the form of a current distribution, the same as that of the ACGF. The IDM can be optimized with the radiation pattern of the modeled antenna, which can be measured without a numerical simulation. The CAD model is not required, and only an approximate dimension of the antenna is used. A CAD model of a seven-patch array antenna with a large platform and a manufactured single Yagi antenna are used to verify the proposed scheme. For verification, we calculate the active element pattern (AEP) based on the ACGF for the antennas. These AEPs calculated, based on the ACGF obtained by MoM, are compared with those calculated on the basis of the IDM. The AEPs represent a sufficient coincident tendency and the phase values are even more accurate than the existing scheme.

A Compact Wideband Slot-Loop Directional Antenna for Marine Communication Applications

A compact wideband high gain directional antenna is proposed in this paper for marine communications. The antenna consists of a back plane (reflector), a slot-loop antenna (driven element), and a director of rod. Based on the current distribution, the slot-loop antenna is equivalent to an array of three linear current dipoles. The dipole acts as an element of the director, which provides a high efficient director for slot-loop antenna according to theoretical analysis. Both the impedance bandwidth and the 1 dB gain bandwidth are 45% covering 1.7–2.7 GHz in this design. A gain of 11.2 to 12.2 dBi is obtained in the working band with only one set of directors. The directors have a dimension less than the antenna aperture in the H-plane, which can be seen as one director in the end-fire direction. Compared with the classic Yagi antenna with the same gain level, the newly proposed antenna is only half of the size in radiation direction, which is a breakthrough for the Yagi antenna design. This size reduction can significantly minimize the interference between ship-borne antennas. The antenna is fabricated using only metal of low cost, which is useful for the ship-to-shore/ship communicating applications and desirable for the large-scale deployment.

A planar end‐fire circularly polarized complementary Yagi antenna

AbstractA novel end‐fire circularly polarized (CP) antenna is presented by integrating a vertically polarized magnetic Yagi array, a horizontally polarized electric Yagi array, various lengths of the directors and common driven elements. Slots with nine Jesus crosses are etched on the common driven elements to extend the impedance matching bandwidth of magnetic Yagi array, while various length of directors are employed to obtain wide axial ratio (AR) bandwidth. The designed CP antenna is both numerically and experimentally validated, and experimental results agree well with electromagnetic simulated results. The fractional impedance bandwidth for ∣S 11∣ < 10 dB is up to 20.7%, and AR bandwidth of less than 3 dB is up to 16.0% in fraction.

3D Printing Using a 60 GHz Millimeter Wave Segmented Parabolic Reflective Curved Antenna

This paper proposes a segmented parabolic curved antenna, which can be used in the base station of a 60 GHz millimeter wave communication system, with an oblique Yagi antenna as a feed. By analyzing the reflection and multi-path interference cancellation phenomenon when the main lobe of the Yagi antenna is reflected, the problem of main lobe splitting is solved. 3D printing technology relying on PLA (polylactic acid) granule raw materials was used to make the coaxial connector bracket and segmented parabolic surface. The reflective surface was vacuum coated (via aluminum evaporation) with low-loss aluminum. The manufacturing method is environmentally friendly and the structure was printed with 0.1 mm accuracy based on large-scale commercial applications at a low cost. The experimental results show that the reflector antenna proposed in this paper achieves a high gain of nearly 20 dBi in 57–64 GHz frequency band and ensures that the main lobe does not split.

VHF Radar Observations of Sea Surface in the Northern Taiwan Strait

Abstract A VHF pulsed radar system was set up on the Taoyuan County seashore (24°57′58″N, 121°00′30″E; Taiwan) to observe the sea surface in the northern Taiwan Strait for the first time. The radar used a four-element, vertically polarized Yagi antenna to transmit the 52-MHz radar wave. The receiving linear array consists of four vertical dipole antennas that were located 3 m apart and attached with four independent and identical receivers. With the multichannel echoes, the direction of arrival (DOA) of the radar echoes were determined by using an optimization beamforming approach—the Capon method. Echo intensity was observed to vary principally in semidiurnal oscillation, which matched well the time series of tide gauge measurements and sea level simulations. In addition, the oscillatory characteristics of Doppler/radial velocity of the VHF radar were generally consistent with that of the HF coastal ocean dynamics applications radar (CODAR) nearby. Nevertheless, the contributions of various tidal modes to the parameters of DOA, echo intensity, radial velocity, and spectral width, varied with the range and time period (e.g., neap or spring tides). For example, the semidiurnal tides governed the variation in the echo center only in the range interval between ~15 and ~25 km from the seashore but dominated other parameters throughout the detectable range. Correlations and phase relationships between these parameters were diverse; they varied with time and had dramatic changes at around the distances of 3 and 10 km. Possible causes of these features were discussed, including sea surface wind, nearshore current, sea level height, and bathymetric effect.

Installation of UiTM’s ground station – Connecting earth and space with amateur band communication

This paper portrays the installation of UiTM’s Ground Station as being part of BIRDS Ground Station Networks; with its main task being to support BIRDS-2 nanosatellite’s monitoring. UiTMSAT-1, UiTM’s first nanosatellite, is one of the BIRDS-2 nanosatellites. It is expected to be deployed from International Space Station (ISS) by middle of 2018. The ground station is installed with two (2) Yagi antennas which operates in Amateur bands respectively at Very High Frequency (144 MHz -148 MHz) ranges and Ultra High Frequency (430 MHz - 438 MHz) ranges. Additionally, an APT antenna for 137 MHz-band polar-orbiting weather satellites is also installed at this ground station for earth weather monitoring. As for security and monitoring matters, lightning/surge protection system and surveillance system (CCTV) also has been installed. Conclusively, several tests had been done as confirmation on the equipment setup. The testing procedure includes receiving HORYU-4 and IO-86 satellite’s signal, and evaluating NOAA satellites’ processed data of South East Asia’s coverage. The uplink communication test, with cooperation with satellite owner, is left for future planning.

NorSat-2: Enabling advanced maritime communication with VDES

Satellite AIS is well recognized as a system for vessel traffic monitoring and maritime safety. The growing demand for maritime data services has led to the development of a new VHF Data Exchange System (VDES), which will provide two-way communication at higher data rates than possible with current AIS systems. Within the VHF maritime frequency band (156.025–162.025 MHz), VDES integrates AIS with channels for Application Specific Messages (ASM) to support the distribution of maritime data, including meteorological data and traffic information. Expanding VDES to a satellite platform will facilitate a global data exchange between ships and shore via satellite. NorSat-2 is the first satellite to incorporate a VDES payload, in addition to an advanced AIS receiver, both of which are in-orbit reconfigurable software-defined radios developed by Kongsberg Seatex.NorSat-2 was developed and built by the Space Flight Laboratory (SFL) under contract to the Norwegian Space Centre, with contribution from Space Norway for accommodation of the VDES payload. With a mass of 16 kg, the satellite design is based on SFL's Next-generation Earth Monitoring and Observation (NEMO) bus, which has proven flight heritage to be a robust and reliable microsatellite platform. To enable directional communication over VHF for the VDES payload, SFL has developed a three-element deployable Yagi-Uda antenna. The antenna is stowed during launch and deployed on-orbit upon command receipt. In addition to NorSat-2's S-band telemetry and command system, the satellite also has an enhanced S-band feeder uplink which is capable of achieving data rates of up to 1 Mbps.NorSat-2 launched onboard a Soyuz on July 14, 2017 into a 600 km polar sun synchronous orbit. It is the fourth Norwegian satellite on-orbit and is one of the first satellites to supply VDES services, in addition to complementing Norway's existing satellite AIS network.This paper describes the NorSat-2 mission, with an emphasis on the unique and innovative aspects that are the VDES payload, deployable Yagi antenna, and enhanced S-band uplink.

Wideband filtering Yagi antenna array

ABSTRACTA novel wideband high-gain antenna array with filtering response is presented. The proposed array consists of four Yagi antenna elements and one feeding network, which could realize signal filtering, power splitting as well as impedance transforming characteristics simultaneously. The operating mechanism is analysed and the detailed design procedure is presented. For demonstration, a 2×2 array is designed at the center frequency of 3.0 GHz with the measured fractional bandwidth of 73.3%. Measured in-band maximum gain is 13.2 dB, whereas the out-of-band suppression level is better than 23.2 dB. Compared with the conventional array, the proposed filtering array shows high suppression in the stopband, good selectivity at passband edges and flat antenna gain in the passband. The simulated and measured results provide a good verification for the theoretical concepts.

Wideband filtering Yagi antenna array

ABSTRACTA novel wideband high-gain antenna array with filtering response is presented. The proposed array consists of four Yagi antenna elements and one feeding network, which could realize signal filtering, power splitting as well as impedance transforming characteristics simultaneously. The operating mechanism is analyzed and the detailed design procedure is presented. For demonstration, a 2 × 2 array is designed at the center frequency of 3.0 GHz with the measured fractional bandwidth of 73.3%. Measured in-band maximum gain is 13.2 dB, whereas the out-of-band suppression level is better than 23.2 dB. Compared with the conventional array, the proposed filtering array shows high suppression in the stopband, good selectivity at passband edges and flat antenna gain in the passband. Simulated and measured results provide a good verification for the theoretical concepts.

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.

Design and Implementation of Dual-Stacked Identical Yagi Antenna for UHF Applications

Design and Implementation of Dual-Stacked Identical Yagi Antenna for UHF Applications

A Novel Chebyshev Series Fed Linear Array with High Gain and Low Sidelobe Level for WLAN Outdoor Systems

This paper proposes a novel high gain and low sidelobe level (SLL) linear microstrip array antenna for outdoor WLAN applications. The antenna consists of two main parts, which are a linear array and a reflector. The linear array comprises of 10 elements; those have been designed on Rogers RT/Duroid 5870tm with the dimensions of 422×100×10.15 mm3. To gain low SLLs, a series fed network was designed to have the output signals being proportional to the Chebyshev distributions (with preset SLL of -30 dB). Furthermore, Yagi antenna theory has been applied by adding directors above every single element to increase the directivity of the single element. The reflector has been constructed at the back of the proposed structure. Simulation results show that the array can provide high gain of 17.5 dBi and a low SLL of -26 dB. A prototype has been fabricated and measured. Good agreements between simulation and measurement data have been obtained.

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.