Planar quasi-Yagi Antenna Research Articles

A Planar Absorptive-Branch-Loaded Quasi-Yagi Antenna With Filtering Capability and Flat Gain

A planar quasi-Yagi antenna with cointegrated filtering functionality and flat in-band gain is reported. It exploits complementary-diplexer-based reflectionless-filtering techniques through the inclusion of an absorptive branch to realize the codesigned filtering functionality. This absorptive branch consists of a second-order bandstop-filter (BSF) unit loaded by a grounded resistor that is connected in parallel with the initial planar quasi-Yagi antenna. By designing the reflection coefficients of the basic antenna and the absorptive branch to be nearly complementary in frequency, the out-of-band RF power not radiated by the antenna is transmitted by the BSF to its loading resistor that dissipates it. In this manner, a quasi-absorptive filtering action is added to the antenna. Moreover, whereas the out-of-band radiation efficiency of the antenna is highly suppressed, its in-band behavior is kept as the in-band RF power is not transmitted by the BSF but radiated by the antenna as usual. For the experimental-validation purposes, a microstrip antenna prototype is developed and measured. Flat in-band gain with a ripple lower than 1 dB within the operational range of the antenna (2.6-3.06 GHz) is obtained as an added merit.

Compact Shared Aperture Quasi-Yagi Antenna With Pattern Diversity for 5G-NR Applications

A novel shared aperture planar quasi-Yagi antenna with complementary pattern (as well as polarization) diversity performance is presented for fifth generation (5G)-new radio (NR) application. A shared aperture antenna with high port isolation and a compact size is first proposed by the even-odd mode feedings. Then, by combining the monopole and dipole modes, the novel pattern reconfigurable method is studied step by step using the surface current distribution. By controlling the feeding states of the monopole and dipole elements, a pattern reconfigurable Yagi antenna with four modes (omnidirectional, broadside, and two tilted patterns) is realized. The quasi-Yagi antenna, which exhibits a compact size of 0.511λ <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">0</sub> ×0.244λ <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">0</sub> ×0.005λ <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">0</sub> , is fabricated and measured for experimental verification. The measured -10 dB bandwidth of the four modes all basically covers the 5G-N78 band 3.3-3.8 GHz (14.1%). The measured peak radiation efficiency is greater than 80%. The proposed compact antenna, with the advantages of low-cost, simple design, good bandwidth, and radiation performance, and pattern/polarization reconfigurability, is well situated for 5G-NR communication.

Wide-Angle Frequency-Scanning Array Antenna Using Dual-Layer Finger Connected Interdigital Capacitor Based CRLH Unit Cell

In this paper, a wide-angle frequency-scanning array antenna is presented for three-dimensional (3D) radar. Initially, a modified composite right/left-handed (CRLH) unit cell based on a dual-layer finger-connected interdigital capacitor (FCIDC) is analyzed. Compared with its conventional counterpart, the proposed unit cell eliminates the undesired high-order resonances and has a lower right/left-handed passband. Then, a broadband frequency-scanning feeding network, which has a large scanning angle, is designed using the proposed CRLH unit cell. The responses of the four output ports indicate that the network can offer desired amplitude and phase difference to scan towards both negative and positive elevation angles. To validate its performance, a tightly coupled planar quasi-Yagi antenna array is fed to synthesize an array antenna. The measured results show that the designed array antenna has an impedance bandwidth ($\vert \text{S}_{11}\vert <; -10$ dB) of 118.7% (2.55-10 GHz) and gains larger than 5dBi in the bulk of the band. Besides, the radiated beam can scan from -47° to 46° continuously when the frequency ranges from 3GHz to 9GHz.

A Compact Planar Quasi-Yagi Antenna With Bandpass Filtering Response

A planar quasi-Yagi antenna with bandpass filtering response is presented. The quasi-Yagi antenna consists of a double-sided printed driven dipole, an offset double-sided parallel-strip line (DSPSL) director, a DSPSL reflector, and an offset DSPSL parasitic element. Both the reflector and the parasitic element can produce an extra radiation null at the band-edges of the passband, and the parasitic element can also generate an additional resonance within the passband. As a result, a compact wideband quasiYagi antenna with quasi-elliptic bandpass filtering response is obtained, without requiring any extra filtering circuit. In addition, the antenna is fed by a balanced DSPSL, and therefore, no balun is needed, leading to a very simple feeding structure. For demonstration, a prototype operating at 2.4 GHz was designed and measured. The prototype has a low profile of 0.006λ0, a -10-dB impedance bandwidth of 30.4%, an average gain of 5.7 dBi over the passband, and an out-of-band suppression level of about 20 dB in the near stopbands.

A Balanced Filtering Quasi-Yagi Antenna With Low Cross-Polarization Levels and High Common-Mode Suppression

A balanced planar quasi-Yagi antenna integrated with a bandpass filtering response is presented in this paper. The proposed balanced antenna consists of a balanced stepped-impedance microstrip-slotline transition structure, a driver dipole, a parasitic strip, and a bandpass filtering unit. A good differential-mode (DM) passband selectivity is formed by inserting a microstrip stub-loaded resonator (SLR) in the feed line of the quasi-Yagi antenna. This integration enables the antenna to achieve both compact size and high frequency selectivity. By controlling the dimensions of SLR, the central frequency and fractional bandwidth (FBW) can be easy to be adjusted. Meanwhile, the microstrip-slotline transition structure can achieve a good wideband common-mode (CM) suppression without affecting the DM ones, thus simplify the design procedure. The proposed antenna with low cross-polarization level and high CM rejection is found to be comparable to the conventional quasi-Yagi antenna. Furthermore, there are two radiation nulls on both sides of the passband to improve the selectivity effectively. In order to validate its practicability, the balanced antenna is designed and fabricated. The experimental results exhibit that the designed balanced filtering antenna features good filtering response, low cross-polarization level, and high CM rejection.

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.

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.

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

Planar quasi‐Yagi antenna with band rejection based on dual dipole structure for UWB

Aiming to realise an end-on-fire antenna with band rejection for ultra-wideband (UWB) system, a planar quasi-Yagi antenna with dual-dipole structure is proposed. The antenna comprises of a coupling transition structure, two stripes and a dual-dipole connected by a coplanar stripline. The compact arrangement of the dual-dipole generates reverse currents at some specific frequency points on their edges, giving rise to phase offsets in far field. This mechanism is used to design band rejection. Simulated and measured results show that the proposed antenna has a bandwidth from 3.08 to 11.1 GHz, which covers the whole UWB band. Meanwhile, the antenna achieves a band rejection from 5.12 to 6.08 GHz, which avoids wireless local area network interference. In pass-band, the antenna achieves a moderate gain, from 4.6 to 7.1 dBi.

Planar Dual-Frequency Quasi-Yagi Antenna

ABSTRACTThe modified dual-frequency printed quasi-Yagi antenna has been designed. After multi-step optimization, the S11 parameter of the antenna is as low as −27 and −14 dB at f01 = 1.7 and f02 = 2.45 GHz, respectively. The antenna directivity is 7.1 and 5 dB at f01 = 1.7 and f02 = 2.45 GHz, respectively. The total length of the planar dual-frequency quasi-Yagi antenna is 158 mm. The universal algorithm of the antenna design has been proposed, and the algorithm can be applied to the creation of three-frequency printed quasi-Yagi antennas.

Compact quasi‐Yagi antenna with folded dipole fed by tapered integrated balun

Planar quasi-Yagi antennas including a printed balun are designed and experimentally characterised. The parasitic array driver is a folded dipole connected to a parallel stripline. The unbalanced to balanced transition between the input microstrip and the folded dipole terminals is obtained by linearly tapering both the microstrip and the ground plane widths. These printed antennas are more compact and directive than their counterparts based on resonant half-wavelength dipole drivers: indeed, in the presence of one director, the size of the board is about 0.4 λ0 × 0.5 λ0 and the measured gain is 7 dB.

Matching and radiation characteristics of a phased array based on quasi-Yagi planar antennas with an additional screen

This article presents the results of numerical investigation and optimization of matching and radiation characteristics for a single planar quasi-Yagi antenna and for a planar phased antenna array (PAA) with size 11×11 elements, which is designed based on these radiators. The research has been performed utilizing the finite difference time domain technique. The calculations have taken into account the presence of an additional metal screen behind the radiating curtain and the feeding of each array’s element via the coaxial-to-microstrip transition, that has made the model of an array as close as possible to the real PAA design and to its performance under real conditions. The levels of electromagnetic coupling between adjacent array elements have been investigated, the variations of operating characteristics of elements in its structure have been demonstrated in the case of in-phase excitation and in the scanning mode. It has been found that the possible scanning sector of this screened PAA falls within the range ±45° for the reflection coefficient of any array’s element, which is less than −10 dB in the frequency range not less than 10%, and for the central element of an array the corresponding operation frequency range exceeds 30% for the scanning in E-plane and it is larger than 17% for the scanning in H-plane.

A Wideband Multilayer Quasi-Yagi Antenna with a Simplified Microstrip-to-CPS Transition Based on LTCC Technology

In this article, a wideband multilayer quasi-Yagi antenna using low temperature cofired ceramic technology is presented. The antenna is fed by a simplified microstrip-to-coplanar strip transition, which serves as balun and impedance transformer simultaneously. Multilayer directors are flared to direct the antenna propagation toward the end-fire direction. Compared with the traditional planar quasi-Yagi antenna, they can suppress the surface waves significantly and provide better director effect to improve the radiation performance. Furthermore, they excite multiple adjacent resonant modes to broaden the bandwidth. The measured results show that the proposed antenna achieves a wide bandwidth of 60% for S11 < −10 dB (26.8–49.8 GHz), better than 12 dB front-to-back ratio, smaller than 16 dB cross polarization and 4.5–6.9 dBi gain within the bandwidth. © 2013 Wiley Periodicals, Inc. Microwave Opt Technol Lett 55:1959–1963, 2013

지상파 디지털 방송 수신용 소형 반 보우 타이 형 준-야기 안테나

본 논문에서는 지상파 디지털 방송 수신용 광대역 평면 야기 안테나의 설계방법에 대해 연구하였다. 다이폴을 급전하는 코플래너 스트립은 스트립에 내장된 마이크로스트립과 연결되고 종단은 단락되어 있다. 급전되는 다이폴에 근접한 영역에 폭이 넓은 직사각형 스트립 도파기를 부가하여 광대역 임피던스 정합과 고주파 대역의 이득특성을 구현하였고, 접지면 반사기를 추가하여 저주파 대역의 이득 특성을 개선하였다. 안테나를 소형화하기 위해 다이폴과 반사기의 모양을 반 보우-타이(V) 형으로 변형하였으며, 여러 가지 파라미터들이 안테나 특성에 미치는 영향을 관찰하였다. 제안된 구조의 안테나를 지상파 DTV 주파수 대역인 470-806 MHz 대역에서 동작하도록 설계하였다. 최적화된 안테나를 FR4 기판 상에 제작하고 특성을 실험한 결과 VSWR < 2 인 대역 450-848 MHz, 이득 > 4.1 dBi, 전후방비 > 10.4 dB 등의 우수한 성능을 갖는 것을 확인하였다. In this paper, we introduce a design method for a broadband planar quasi-Yagi antenna (QYA) for terrestrial digital television (DTV) reception. The coplanar strip line which feeds the driver dipole is connected to a microstrip line and is terminated by short circuit. By appending a wide strip-type rectangular director at a location close to the driver dipole, broadband impedance matching and gain enhancement in a high frequency region are obtained. The gain characteristics in a low frequency region are improved by adding a reflector formed by a truncated ground plane. To reduce the antenna size, the strip-type dipole and reflector are modified to half bow-tie (V)-shaped elements. The effects of various parameters on the antenna characteristics are examined. An antenna, as a design example for the proposed antenna, is designed for the operation in the frequency band of 470-806 MHz for terrestrial DTV. The optimized antenna is fabricated on an FR4 substrate and the experimental results show that the antenna has a good performance such as a frequency band of 450-848 MHz for a VSWR < 2, gain > 4.1 dBi, and front-to-back ratio > 10.4 dB.

Modified broadband quasi-Yagi antenna with enhanced gain and bandwidth

This article presents a method for improving the gain and bandwidth of a microstrip-fed broadband planar quasi-Yagi (QY) antenna.To obtain a better and more stable gain with little variation over a broad frequency band, we used a planar QY antenna with strip-type elements (a driver dipole and two directors) that had unequal widths and unequal spacing between them. First, to achieve a broad bandwidth of over 50%, a wide strip is used as a nearby director placed very close to the driver dipole. Then, to enhance and stabilize gain over a required frequency band, a narrow strip director and a ground reflector are appended to the driver with a nearby parasitic director. We systematically explain the effect of each element on the input impedance and the realized gain. To validate this proposed design, a QY antenna with a frequency band from 1.75 to 2.7 GHz and a gain of over 5 dBi was designed, then fabricated on an FR4 substrate, and tested. The results show that the fabricated antenna performs well, with a broad bandwidth of 60.4% (1.53–2.85 GHz), a stable gain between 5.38 and 6.41 dBi, and a front-to-back ratio of over 10 dB. © 2012 Wiley Periodicals, Inc. Microwave Opt Technol Lett 55:406–409, 2012; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.27325

이동통신 기지국용 광대역 quasi-Yagi 안테나에 관한 연구

In this paper, a method for the improvement in the gain and bandwidth of a microstrip-fed broadband planar quasi-Yagi antenna (QYA) is studied. The broadband characteristics of the QYA are achieved from the coplanar strip-fed planar dipole driver and a parasitic director close to the driver. In order to obtain stable gain variation over the required frequency band, a director and a ground reflector are appended to the driver having a nearby parasitic director. The QYA is fed through an integrated balun composed of a microstrip line and a slot line which are terminated in a short circuit. By adjusting the feeding point, a broadband impedance matching is obtained. A QYA with an operating frequency band of 1.75-2.7 GHz and a gain > 4.5 dBi is designed and fabricated on an FR4 substrate with dielectric constant of 4.4 and thickness of 1.6mm. The experimental results show that the fabricated antenna has good performance such as a broad bandwidth of 59.7%(1.55-2.87 GHz), a stable gain between 4.7-6.5 dBi, and a front-to-back ratio > 10 dB. The measured data agree well with the simulation, which validates this study.

Design of a Multiband Quasi-Yagi-Type Antenna With CPW-to-CPS Transition

A novel coplanar waveguide-fed planar quasi-Yagi antenna for multiband operation is presented in this letter. The antenna consists of a basic quasi-Yagi element and a coplanar-waveguide-to-coplanar-strip (CPW-to-CPS) transition, which can excite the odd-mode electric fields at the CPS line though the CPW feed line. The proposed antenna can be used in multiband operation with directional radiation patterns whose front-to-back ratios approximate to 10 dB for desired bands. Its impedance bandwidth, determined by -10-dB reflection coefficient, covers numbers of present wireless communication systems, and the antenna can be simply integrated with other circuit components for its planar structure. Experimental data obtained from a laboratory prototype are also presented. The experimental results confirm the good performances observed by the electromagnetic simulations.

Frequency Reconfigurable Quasi-Yagi Folded Dipole Antenna

A frequency reconfigurable planar quasi-Yagi antenna with a folded dipole driver element is presented. The center frequency of the antenna is electronically tuned by changing the effective electrical length of the folded dipole driver, which is achieved by employing either varactor diodes or PIN diodes. Two antenna prototypes are designed, fabricated and measured. The first antenna enables continuous tuning from 6 to 6.6 GHz using varactor diodes and the reflection coefficient bandwidth (≤ -10 dB) at each frequency is greater than 15%. The second antenna enables discrete tuning using PIN diodes to operate in either the 5.3-6.6 GHz band or the 6.4-8 GHz band. Similar end-fire radiation patterns with low cross-polarization levels are achieved across the entire tunable frequency range for the two antenna prototypes. Measured results on tuning range, radiation patterns and gain are provided, and these show good agreement with numerical simulations.

Compact E-band planar quasi-Yagi antenna with folded dipole driver

A broadband planar quasi-Yagi antenna using a folded dipole driver is presented. The new antenna element is realised on a low dielectric constant substrate and it is suitable for millimetre-wave applications using low-cost thick-film fabrication. The advantage of the quasi-Yagi antenna with folded dipole driver compared to the standard quasi-Yagi antenna is a reduction in the length of the driver, which allows closer spacing of the elements for array applications on low dielectric constant substrates. Use of the folded dipole driver gives a 4:1 impedance range because of its extra parameters. The element was designed for E-band applications, but operates over a much wider bandwidth of approximately 1.3:1. Mutual coupling between two antenna elements in an array environment is investigated and results obtained are similar to conventional quasi-Yagi antenna elements. Four linear arrays, each containing four elements and having a different beamforming network, were fabricated to demonstrate the scanning capabilities of the folded dipole quasi-Yagi antenna, and measured reflection coefficient, radiation patterns and gain for each array are presented.