Basic Antenna Element Research Articles

A Parallel Folded Dipole Antenna With an Enhanced Bandwidth for 5G Millimeter-Wave Applications

In this communication, a planar folded dipole antenna array with wide operating bandwidth and compact size is proposed for 5G millimeter-wave (mmWave) applications. The basic antenna element is a pair of parallel folded dipoles (PFDs) connected at the terminals. Compared with a single half-wavelength dipole, the PFD can achieve a flatter impedance curve in the working frequency band, and it is easier to achieve broadband impedance matching with 50Ω feeding line. Moreover, a coupling slot feeding method is adopted to feed the proposed antenna element. The capacitance provided by the coupling slot can counteract the inductance caused by the PFD, thus improving the impedance matching at the low frequency band. Benefiting from the innovative design, the proposed antenna element can achieve an ultra-wide impedance bandwidth of 64% and a compact size of 0.26λ <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">0</sub> × 0.28λ <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">0</sub> . Furthermore, a wide scanning angle with ±50° over wide bandwidth is testified by a 1×8 array using active simulation. For verification, a 4×4 full corporate-fed array is designed based on the proposed element. The measured results prove that the proposed 4×4 array has a -10 dB impedance bandwidth of 65% covering 17 to 33.75 GHz and a peak gain of 17.5 dBi. The measured total efficiency is from 69% to 82% over the working frequency band. With the merits of compact size, wide working bandwidth, and wide beam scanning angle, the proposed antenna is a good candidate for mmWave wireless communications.

A Compact, Low-Profile Shorted TM$_{1/2,0}$ Mode Planar Copolarized Microstrip Antenna for Full-Duplex Systems

In this letter, a single-layer compact copolarized shorted TM <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">1/2,0</sub> mode microstrip patch antenna is presented for in-band full-duplex application. Two shorted TM <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">1/2,0</sub> mode patch antennas, used for transmission and reception purposes, make the structure compact. The wideband behavior of the patch antenna is obtained by fusing the two resonances, one because of the shorted TM <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">1/2,0</sub> mode radiating patch and the other because of the λ/4 line resonator. To enhance the isolation between the transmitter and receiver antenna, a novel defected ground structure is used. Slots are introduced into the ground plane to create a weak field region for the basic antenna element. The other antenna element (receiver) is located in the weak field region to enhance isolation. Further enhancement in isolation is achieved by introducing a T-shaped metallic strip into the slots. The structure is proposed with the credits of compactness, enhanced bandwidth, colinear polarization, very less fabrication complexity, low profile, and high isolation. The proposed structure is fabricated and measured. The structure experimentally exhibits a bandwidth (≤ −10 dB) of 2.42–2.52 GHz with the isolation of 25 dB, peak isolation of 36 dB, and an average realized gain of 4 dBi in the entire band.

Unequally Spaced Scalable dual-polarized Ultra-wideband Antenna Array with Slot Positioning for Large Scale Array

ABSTRACT article shows a splicable dual-pol. ultra-wideband array antenna used in large-scale arrays. An unequal-spaced metal bullet structure is used as the basic antenna element, and the gradual slot for radiation is spliced by the metal bullet radiator. The bullet structure is directly and vertically interconnected through elastic RF connectors. The antenna structure can be independently installed on the metal backplane and positioned through the slots on the metal backplane to ensure good electrical performance. Compared with the antenna structure processed by PCB technology, this type of antenna can effectively avoid the generation of surface wave modes, thereby ensuring that there is no VSWR singularity in the broadband. The proposed antenna array can realize ±45°scanning in azimuth plane and ±35°scanning in elevation plane within four octave bands. Based on the proposed antenna, a 10*10 prototype was tested. The measured results were consistent with the simulation results.

Design of an interlocked four-port MIMO antenna for UWB automotive communications

AbstractThe design, analysis, fabrication, and testing of a four-port multiple-input multiple-output (MIMO) antenna is reported in this paper for automotive communications. The MIMO antenna is constructed using the basic antenna element exploiting a slot geometry. Two such antennas are developed on the same microwave laminate to develop a two-port MIMO antenna. Two such microwave laminates are interlocked to create the four-port MIMO scheme. The most distinct feature of the proposed architecture is that the inter-port isolation is well-taken care without the need for an external decoupling unit. The four-port MIMO antenna has an overall volume of 32 × 15 × 32 mm3. The prototype MIMO antenna is fabricated and the measurements are carried out to validate the simulation results. The antenna offers ultra-wideband (UWB) characteristics covering the frequency range of 2.8–9.5 GHz. The average boresight gain of the antenna ranges from 3.2 to 5.41 dBi with the peak gain at 8 GHz. The simulated efficiency of the antenna is greater than 73% within the operating bandwidth. The MIMO parameters such as envelope correlation coefficient, diversity gain, and mean effective gain are evaluated and presented. The appropriateness of the proposed antenna for deployment in the shark fin housing of the present-day automobiles is verified using on-car performance estimation.

Transverse slot with control of amplitude and phase for travelling‐wave SIW antenna arrays

A novel basic antenna element for travelling-wave substrate integrated waveguide (SIW) arrays is proposed in this study. The antenna element is based on a transverse slot and newly complemented by a pair of vias used for matching and a phase shifter. By changing the geometries of the slot and the phase shifter, the amplitude and phase of a radiated wave can be controlled. The proposed approach extends the potential of transverse slots in SIW-based travelling-wave antenna arrays. To verify the capabilities of the antenna element, the authors demonstrate a six-element array with side-lobe suppression, intended for a 24 GHz radar system. The measured results show good agreement with simulations.

ANALYSIS OF CONFORMAL TRIPLE NOTCH ANTENNA FOR C, X AND KU BAND COMMUNICATION

A compact conformal antenna for wireless communication applications is proposed in this paper. For the basic antenna element, bending analysis at 15, 30 and 45 degrees is discussed. The proposed antenna dimensions are 26x24x1.6 mm3. Flexible material Rogers Ultralam is used as substrate material in HFSS simulation. Simulation results of planar antenna and the proposed conformal antenna at different bending angles are investigated and analyzed. The results show that the proposed antenna has good antenna performance parameters even for different bending angles and thus this antenna can be integrated on to any surface for various wireless applications.

On the multi‐resonant antennas: Theory, history, and new development

A survey of multi-resonant antennas is comprehensively presented, with emphasis on theoretical framework, design approaches, and practical examples. This article begins with a brief history of the multi-resonant dipole theory, and then concentrates on the design approaches that have been developed to typical, basic antenna elements, for example, electric dipole antenna, slotline antenna, loop antenna, complementary dipole antenna, and microstrip patch antenna. Design examples for different practical applications are then raised. In final, the multi-resonant antenna design approach is summarized and compared to some relevant antenna design techniques.

A COMPACT AND WIDEBAND FLAT LENS ANTENNA BASED ON APERTURE COUPLED PATCHES FOR X-BAND APPLICATIONS

This paper presents a wideband and compact flat lens antenna for X-band applications. An 8×8 array of this antenna is designed and realized by using aperture coupled patches from the multilayer Frequency Selective Surface concept. The basic antenna element configuration of this design consists of two back-to-back printed patches with a common ground plane coupling. A pair of identical slots is embedded on the ground plane to provide the necessary phase error compensation between receive and transmit apertures. The lengths of the two slots are varied simultaneously to investigate how much phase shift range can be achieved with this simple design structure. The antenna elements are simulated using the electromagnetic simulation software CST Microwave Studio. A 209° transmission phase range was achieved with transmission coefficient variations of better than -2.25 dB. The gain of the feeding horn antenna used is 9 dB at 10 GHz. Upon the implementations of the lens structure, the gain of the overall antenna system has increased to 16 dB. Our simulation shows a 3-dB transmission bandwidth of around 33% could be achieved for the unit cell. Radiation pattern simulation of the antenna system shows a good symmetry between E and H-plane with a half-power beamwidth of 19.2° and 19.0° in E-plane and H-plane respectively. The gain is greater than 9 dB from 8 to 12 GHz with maximum gain of 16 dB is achieved at 10 GHz. The proposed antenna design uses a simple and less fabrication complexity mechanism for phase error correction.

Analysis of spatial/polarization diversity using a broadband slot‐coupled patch antenna for the WLAN 802.11A/B/G/N access point

ABSTRACTA broad dual‐band slot‐coupled patch antenna is proposed for the wireless local area network band. The basic antenna element consists of two radiators on three layers. To enhance the bandwidth, a coupled feeding was used in the first radiator, and a parasitic patch was used in the second radiator. The peak gain of the single antenna element was more than 6 dBi at 2.4 GHz and more than 8 dBi at 5 GHz. We simulated and measured the extended antenna to four elements using a common reflector, and the spatial and polarization diversity of the proposed antenna were analyzed according to the isolation and the diversity gain. The isolation is below −15 dB at the operating frequency when the distance between the proposed antennas is more than 0.67λ (80 mm). The orthogonal polarization of the proposed antenna obviously improves the performance of the diversity antenna system. © 2015 Wiley Periodicals, Inc. Microwave Opt Technol Lett 57:1042–1048, 2015

A Tutorial on the Receiving and Scattering Properties of Antennas

A tutorial discussion on the receiving and scattering properties of antennas is presented. The objective of this work is to provide a comprehensive tutorial overview of the subject, in conjunction with circuit calculations and numerical simulations that illustrate the fundamental concepts of how antennas behave as both receivers and scatterers of electromagnetic fields and power. The paper begins with a discussion of the basic concepts associated with antenna impedance, as these are fundamental to understanding the antenna's receiving and scattering properties, particularly over a wide range of frequencies, where the circuit properties of the antenna differ. The definitions of aperture efficiency, absorption efficiency, and the validity of using either a Thevenin or Norton equivalent circuit to determine both received and total scattered power are discussed. Circuit circulations and numerical simulations, determining both total received and scattered powers, are presented for a number of antennas, including a straight-wide dipole, a circular loop, a reflector-backed dipole, and a Yagi antenna. We show that Thevenin and Norton equivalent circuits have limited validity when used to determine the total power scattered by a basic antenna element such as the dipole and loop. For the general antenna, these equivalent circuit models are not valid for determining the total scattered power.

Hex‐band antenna for slim handheld device applications

AbstractIn this article, we present an approach and design of a small antenna for slim handheld device applications. The basic antenna element is the monopole. The small size and the reduced effective antenna height are achieved from two folding approaches of this monopole. The first is in a three‐dimensional manner, which also results in a broad bandwidth at the desired operating frequencies. The second is achieved by wrapping the antenna around the PCB. This wrapping reduces the physical antenna height to the minimum height required to accommodate the main components of the device without compromising the antenna performance. The proposed antenna is prototyped and modeled, where its performance is examined through simulations and measurements. The antenna supports six frequency bands, GSM 800/900/1800/1900 MHz, UMTS 2100 MHz, and Bluetooth 2400 MHz. © 2009 Wiley Periodicals, Inc. Microwave Opt Technol Lett 51: 2527–2530, 2009; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.24670

Introduction to "Principles of radio transmission and reception with antenna and coil aerials"

Hertz's discovery of electromagnetic (radio) waves in 1888 and Marconi's dramatic demonstration of trans-Atlantic radio communication in 1901 provided the rapid growth of radio science and radio technology during the early part of this century. John Howard Dellinger's Classic Paper appeared in 1919 when the low-frequency radio technology was developing. A brief history of early radio, a short biography ofDellinger, the main features of the paper, along with afew later developments and conventions used in the area of antennas and wave propagation, are given so that the paper may be better appreciated. The Classic Paper summarizes the fundamentals of radio wave transmission and reception and gives the theory and design of low-frequency linear and loop antennas. Detailed comparative discussions are given for the use of these two basic antenna elements used for transmitting and receiving purposes. Considering the fact that the paper was written almost a century ago, its contents are still found to be surprisingly topical.

Millimeter‐wave optically scanning antenna based on photoinduced plasma grating

The photocontrolled millimeter-wave (MMW) antenna is an alternative approach to the phased array. It offers a high potential to decrease fabrication cost. We describe a new MMW scanning antenna controlled by light. The basic antenna element is a semiconductor plate containing a photoinduced plasma grating (PIPG). By changing the grating period and rotating the grating, the device is able to scan a MMW beam in two dimensions. To enhance antenna efficiency, we use an antenna design that takes advantage of the reflectance of the MMW mirror behind the semiconductor plate. We found that the pulse duration of the pumping light can strongly affect the antenna’s output. Our calculations demonstrate that diffusion is responsible for decay of antenna efficiency.