Antenna Solution Research Articles

Toroidal Plasma Lens Antenna

This letter proposes a novel toroidal plasma lens with circular polarization, as an alternative solution for electronic warfare antennas. The aim of the proposed solution is to reduce the antenna profile and the radar cross section, thus minimizing the probability of target detection. The results compare the performance of the proposed antenna to a conical horn and to a spherical/elliptical lens. The toroidal plasma lens achieved equivalent gain, with reduced antenna profile and reduced near-field backscattering from the plasma toroid, thus maximizing the true power delivered to the far-field region.

Design of a Small-Size, Low-Profile, and Low-Cost Normal-Mode Helical Antenna for UHF RFID Wristbands

Emerging RFID applications in the UHF band in some cases require very specific antenna solutions. This letter considers the identification and tracking of patients inside hospital facilities using wristbands, which impose strict tag size and cost limitations. We propose a solution for passive tags based on a normal-mode helical antenna as an alternative to bulky and/or expensive solutions that can be found in the literature. The robustness of the resulting wristband will be assessed in a particular implementation by measuring the maximum read range for a variety of subjects with different physical constitutions.

Compact 4G MIMO antenna integrated with a 5G array for current and future mobile handsets

A novel integrated antenna solution for wireless handheld devices is proposed for the existing 4G standards and upcoming 5G systems for broadband, high data rate communications. The complete antenna system is a unique combination of a multiple-input-multiple-output (MIMO) antenna system at microwave frequencies and a millimetre (mm)-wave antenna array. The MIMO antenna system consists of two reactive loaded monopoles while the mm-wave array consists of a planar 2 by four slot antennas. The integrated antenna system covers the frequency bands from 1870 to 2530 MHz for 4G standards along with the upcoming 5G mm-wave band at 28 GHz. In addition, the integrated antenna system is planar and is designed for typical smart phone devices with a standard 60 mm by 100 mm by 0.965 mm back plane. Excellent field correlation values were obtained across the 4G band while realised peak gain values of 4 and 8 dBi were, respectively, measured for the MIMO and mm-wave antenna arrays. The proposed antenna design may also be useful for other compact implementations that support 4G and 5G communications.

Wideband Double Monopole for Mobile, WLAN, and C2C Services in Vehicular Applications

In this letter, a three-dimensional antenna solution for automotive applications is presented. The proposed solution is formed by two independent antennas, perpendicularly placed inside a plastic cover with a shark-fin shape. The antennas, designed with low-cost materials, exhibit omnidirectional radiation patterns in the azimuthal plane. The first antenna is a double-shorted monopole that provides service from 698 to 960 MHz (in the LTE700, GSM850, and GSM900 bands), whereas the second antenna is a drop-shaped monopole that operates from 1.7 to 2.7 GHz (in the DCS1800, PCS1900, WCDMA2100, WLAN2400, LTE2600, WiMAX2350, and Wi-Fi at 2.4-GHz bands), and from 5.1 to 6 GHz (in the Wi-Fi at 5 GHz and C2C bands). Results show a good matching and radiation efficiency at all bands.

Integration of antennas with sun‐tracking solar panels

A low-cost solution for antennas integrated into solar cells, allowing their implementation in solar tracking installations is proposed. The proposed passive device autonomously adjusts the phase shift of a two-element array proportional to the panel rotation. Consequently, the main beam is steered to compensate for panel rotation and maintain a radio link. The proposed device operates for a rotation of ±45° with an amplitude variation of ≤0.4 dB at 2.51 GHz.

Metasurface-loaded dielectric rod leaky wave antenna

This paper introduces an analytical solution for a dielectric rod leaky wave antenna loaded by a metasurface. The advantage of adding metasurface on the dielectric rod is that it introduces an additional degree of freedom in the design of this antenna by controlling the outer boundary condition. Modified Generalized Sheet Transition Condition on a cylindrical geometry is used to model the metasurface on the dielectric rod. The analysis is based on developing the characteristic equation of the proposed structure. This characteristic equation is used to obtain the complex propagation constant of this structure and the corresponding field distribution inside and outside the rod including the resulting radiated fields. Parameters of the metasurface are extracted from the reflection and transmission properties of its elements in infinite periodic structure. An example of a dielectric rod loaded by a metasurface is presented analytically based on the introduced analysis and also simulated numerically for comparison. The effect of different polarizabilities of the loading metasurface on the leaky wave properties of the dielectric rod is discussed.

Antenna-assisted picosecond control of nanoscale phase transition in vanadium dioxide.

Nanoscale devices in which the interaction with light can be configured using external control signals hold great interest for next-generation optoelectronic circuits. Materials exhibiting a structural or electronic phase transition offer a large modulation contrast with multi-level optical switching and memory functionalities. In addition, plasmonic nanoantennas can provide an efficient enhancement mechanism for both the optically induced excitation and the readout of materials strategically positioned in their local environment. Here, we demonstrate picosecond all-optical switching of the local phase transition in plasmonic antenna-vanadium dioxide (VO2) hybrids, exploiting strong resonant field enhancement and selective optical pumping in plasmonic hotspots. Polarization- and wavelength-dependent pump–probe spectroscopy of multifrequency crossed antenna arrays shows that nanoscale optical switching in plasmonic hotspots does not affect neighboring antennas placed within 100 nm of the excited antennas. The antenna-assisted pumping mechanism is confirmed by numerical model calculations of the resonant, antenna-mediated local heating on a picosecond time scale. The hybrid, nanoscale excitation mechanism results in 20 times reduced switching energies and 5 times faster recovery times than a VO2 film without antennas, enabling fully reversible switching at over two million cycles per second and at local switching energies in the picojoule range. The hybrid solution of antennas and VO2 provides a conceptual framework to merge the field localization and phase-transition response, enabling precise, nanoscale optical memory functionalities.

Optimum broadband E-patch antenna design with Taguchi method

This paper describes the design of a broadband E-patch antenna using Taguchi method. Although this optimization method exhibits a fast convergence speed, its application to the antenna design has so far been very limited as compared to the particle swarm optimization and differential evolution. Different than the prior work on optimization-based design of E-patch antennas, the presented design is carried out by satisfying multiple objectives: the minimum antenna footprint area and |S11| < −10 dB bandwidth across 5–6 GHz band. The performance of this E-patch antenna design is compared with that of an E-patch antenna designed with the differential evolution algorithm to meet the same |S11| < −10 dB bandwidth criteria. It is shown that a two-level Taguchi method applied to E-patch design problem with 6 degrees of freedom can complete the design with 8 full-wave simulations as compared to the entire 26 = 64 possibilities. This is also considerably faster than the differential evolution algorithm that may require >300 full-wave simulations. In addition, it is shown that the presented design can meet the bandwidth criteria with a smaller footprint, hence demonstrates that minimization of the footprint must also be a part of the design process to achieve the best antenna solution. Furthermore, the E-patch antenna is fabricated and measured to confirm the validity of the proposed design.

A New Approximate Closed Solution for Small Dipole Antenna with Method of Moments

In this paper, an approximate closed-form solution of the impedance coefficient for a small dipole using the method of moments is developed from the reduced or approximate Pocklington equation. As an application, the close-form self-impedance coefficient using the piecewise constant and linear basis functions are found, with well-defined rounding error functions. The authors found that the self-impedance using the piecewise constant basis function is inconsistent with the physics of the problem for segments close to wavelength tenths and arbitrary small wire diameters, independent of the reduced kernel approximation and the printed source model used.

Mm-wave integrated wireless transceiver: enabling technology for high bandwidth short-range networking in cyber physical systems

Emerging application scenarios for Cyber Physical Systems often require the networking of sensing and actuation nodes at high data rate and through wireless links. Lot of surveillance and control systems adopt as input sensors distributed video cameras operating at different spectral ranges and covering different fields of view. Arrays of radio/light detection and ranging (Radar/Lidar) sensors are often used to detect the presence of targets, of their speeds, distance and direction. The relevant bandwidth requirement amounts to some Gbps. The wireless connection is essential for easy and flexible deployment of the sensing/actuation nodes. A key technology to keep low the size and weight of the nodes is the fully integration at mm-waves of wireless transceivers sustaining Gbps data rate. To this aim, this paper presents the design of 60 GHz transceiver key blocks (Low Noise Amplifier, Power Amplifier, Antenna) to ensure connection distances up to 10 m and data rate of several Gbps. Around 60 GHz there are freely-available (unlicensed) worldwide several GHz of bandwidth. By using a CMOS Silicon-on-Insulator technology RF, analog and digital baseband circuitry can be integrated single-chip minimizing noise coupling. At mm-wave the wavelength is few mm and hence even the antenna is integrated on chip reducing cost and size vs. off-chip antenna solutions. The proposed transceiver enables at physical layer the implementation in compact nodes of links with data rates of several Gbps and up to 10 m distance; this is suited for home/office scenarios, or on-board vehicles (cars, trains, ships, airplanes) or body area networks for healthcare and wellness.

A DVC switchable antenna technique for the hand effect in mobile terminals

ABSTRACTA human hand holding mobile terminals causes the impedance mismatch and the signal absorption in the human body and, in result, deteriorates the performance of the mobile terminals. In this letter, we show the hand effect on mobile terminals via appropriate experiments and propose a simple but novel antenna solution that compensates for the mismatch. Our proposed solution exploits the digital variable capacity (DVC), which makes the antenna adapt to the hand effect on mobile terminals. To validate our design, we implement the proposed antenna in band5. Experimental results show that a human hand holding mobile terminals causes losses by 5.39–6.02dB. They also show that the proposed DVC adaptive antenna technique improves the antenna performance as much as 0.47–1.78dB. This study presents new understanding on the effect of DVC that compensates mismatch losses. We believe that antenna designers can exploit this research when optimizing antenna performance. © 2015 Wiley Periodicals, Inc. Microwave Opt Technol Lett 55:2614–2617, 2015

Insole Antenna for On-Body Telemetry

A 433-MHz antenna is proposed for integration with the insole of footwear for a body-area network. The folded dipole design with an asymmetric groundplane radiates from its edges and considers the close proximity of the human foot and ground surfaces. It functions for different ground conductivity conditions and an on-body communication link with an inverted-F antenna in the upper body area was evaluated on a static and dynamic human subject. The antenna solution was compliant with specific absorption rate (SAR) requirements, remains matched and links with upper body nodes regardless of the body posture and node location.

Efficient CMOS Systems With Beam–Lead Interconnects for Space Instruments

One of the main reasons CMOS systems has low overall efficiency is the performance of the on-chip antennas. With the recent severe metal density rules the problem has become more severe. Hence, antenna engineers need to move toward systems-in-package involving off-chip antenna solutions for high-efficiency performance. We introduce a new metal beam–lead interconnection technique which offers better matching control and lower loss at higher frequencies. The metal beam–lead interconnection appears to be a good solution for CMOS circuits at millimeter- and submillimeter-wave frequencies where off-chip connections are required. In this paper, we report performance of a 150 GHz CMOS transmitter which uses metal beam–lead interconnect between a high efficiency silicon antenna and a CMOS transmitter.

Recent advances in antenna design and interference cancellation algorithms for in-band full duplex relays

In-band full-duplex relays transmit and receive simultaneously at the same center frequency, hence offering enhanced spectral efficiency for relay deployment. In order to deploy such full-duplex relays, it is necessary to efficiently mitigate the inherent self-interference stemming from the strong transmit signal coupling to the sensitive receive chain. In this article, we present novel state-of-the-art antenna solutions as well as digital self-interference cancellation algorithms for compact MIMO fullduplex relays, specifically targeted for reduced-cost deployments in local area networks. The presented antenna design builds on resonant wavetraps and is shown to provide passive isolations on the order of 60–70 dB. We also discuss and present advanced digital cancellation solutions, beyond classical linear processing, specifically tailored against nonlinear distortion of the power amplifier when operating close to saturation. Measured results from a complete demonstrator system, integrating antennas, RF cancellation, and nonlinear digital cancellation, are also presented, evidencing close to 100 dB of overall self-interference suppression. The reported results indicate that building and deploying compact full-duplex MIMO relays is already technologically feasible.

Design and Implementation of an RF Coupler Based on YBCO Superconducting Films

A radio-frequency coupler was designed and implemented using high-temperature superconductor (HTSC) YBCO films. A circuit for a single superconducting coupling channel was implemented and serves as the primary component in the multichannel coupling system geometry, allowing a high-power broadcast due to low losses of superconductors below the critical temperature (T c ). In this paper, a solution for the multiple antennas' isolation problem is proposed by reducing the number of antennas to a single antenna. Multichannel transmission systems require high-power broadcasts in order to transmit signals over long distances. A coupling system with low losses was used to improve the system's active performance. In this paper, the system is implemented in a very high-frequency range using a microstrip in meander geometry.

C-Band Multiple Beam Antennas for Communication Satellites

Nowadays, broadband satellites operating at Ka-band and providing high capacity (above 100 Mbps) are mostly based on single-feed-per-beam (SFB) antenna configurations. This antenna farm, using typically three or four reflectors to produce the full dual-band (Tx/Rx) multiple beam coverage, provides high performance but leaves no or little room on the spacecraft for other missions. Accommodation constraints and the desire of operators to maximize and diversify their revenues per satellite have led to several studies on innovative antenna solutions enabling to reduce the number of reflector apertures. Multiple-feed-per-beam (MFB) antenna configurations, using only two apertures, are currently under development for broadband missions at Ka-band. C-band is a more mature business and operators are contemplating the possibility to apply the benefits of multiple beam antennas (MBA) to this frequency band. Due to the lower operating frequency, accommodation constraints are even more stringent and although still scarcely discussed, MFB antenna configurations at C-band are clearly of interest. This paper presents investigations on this topic. In particular, it is found that the MFB architecture applied in C-band is a more realistic approach when compared to the SFB option. Beam Forming Networks (BFNs) with periodic structure is the key to get compact feed clusters that can be allocated in large and medium-size platforms. A new four color scheme compatible with a very compact MFB feed array architecture is introduced.

Indoor radio link characterization studies for millimeter wave wireless communications utilizing dielectric-loaded exponentially tapered slot antenna

A trend that is pragmatic in today’s wireless communications is the demand for the supportof increasing data rates over short distances. Through the last decade, ample knowledge about the 60 GHz millimeter wave (MmW) channel has been gathered and different architectures have been analyzed to develop MmW communication systems for commercial applications. The usage of MmW frequencies is perceived as a resilient entrant for realizing future, gigabit wireless communications as it offer vast bandwidths for short-range indoor communications. In this work, the MmW antenna solutions for exponentially tapered slot (ETS) antenna using substrate integrated waveguide (SIW) technology and indoor radio wave propagations are studied at 60 GHz for wireless communications. The SIW is used to feed the antenna, and a dielectric loading is utilized in front of the antenna to increase the gain. The antenna with elliptical-shaped dielectric loaded is fabricated using printed circuit board process. The measurement results are compared with simulated results. Then, the indoor short-range radio wave propagation study is carried out using ETS antenna with RF measurement equipment to measure and model propagation channels at 60 GHz. The attained simulations are compared to the experimental results.

Reconfigurable Bowtie Antenna Using Metal-Insulator Transition in Vanadium Dioxide

A new method to reconfigure, tune or program an antenna is presented and validated through a fabricated proof-of-concept prototype. The method relies on the changing electrical properties of a smart material, vanadium dioxide ( VO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> ), across its solid-to-solid phase transition. The phase change in the material is induced thermally. The developed device is a monolithically integrated VO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> -based antenna that changes resonant frequency on demand. Details and challenges related to the design, fabrication and integration of VO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> thin films with antennas, as well as the measurement setup, are discussed. Measurement results match well with theory and simulations. Results unveil a new technique for reconfiguring antennas and suggest further studies and improvements could lead to more exciting results and make vanadium dioxide thin-films an alternate solution for multi-functional antennas. This work is the first prototype to implement this new reconfiguration mechanism in antennas in the gigahertz range and to present results during the VO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> metal-to-insulator phase transition.

A Dual-Loop Antenna Design for Hepta-Band WWAN/LTE Metal-Rimmed Smartphone Applications

A simple direct-fed dual-loop antenna capable of providing hepta-band WWAN/LTE operation under surroundings of an unbroken metal rim in smartphone applications is proposed. The greatest highlight of this proposed antenna is that it provides a simple and effective multiband antenna solution for an unbroken metal-rimmed smartphone. The unbroken metal rim with 5 mm in height embraces the system circuit board of 130 $\, \times \,$ 70 mm $^{2}$ . Two no-ground portions of 10 $\, \times \,$ 70 mm $^{2}$ and 5 $\, \times \,$ 70 mm $^{2}$ are set on the top and bottom edge of the system circuit board, respectively. In-between the two separate no-ground portions, there is a system ground of 115 $\, \times \,$ 70 mm $^{2}$ connected with the unbroken metal rim via a small grounded patch which divides the unbroken metal rim into two strips. Finally, a dual-loop antenna is formed by combining the inner system ground and two strips. This proposed dual-loop antenna is capable of covering GSM850/900/DCS/PCS/UMTS2100/LTE 2300/2500 operating bands. Detailed design considerations of the proposed antenna are described and both experimental and simulation results are also presented and discussed.

Design and Performance Evaluation of a Dielectric Flat Lens Antenna for Millimeter-Wave Applications

In this letter, a practical fabrication of a novel inhomogeneous gradient-index dielectric flat lens for millimeter-wave applications is presented. A previous theoretical design of a dielectric flat lens composed of different permittivity materials is now modeled and analyzed for a practical prototype fabrication and performance evaluation at 60 and 77 GHz. The measurement results at 60 GHz show that with the novel gradient-index dielectric flat lens antenna prototype, we can achieve up to 18.3 dB of broadside gain, beam-steering capabilities in both planes from $-30^\circ$ to $+30^\circ$ with around 15 dB of gain, and up to $\pm 45^\circ$ with around 14 dB of gain, with low sidelobe levels. At 77 GHz, the performance evaluation shows that we can obtain up to 18.9 dB of broadside gain, beam-steering capabilities in both planes from $-30^\circ$ to $+30^\circ$ with around 17 dB of gain and low sidelobe levels, and up to $\pm 45^\circ$ with around 15 dB of gain. This novel design leads to a low-cost, low-profile, and lightweight antenna solution, easy to integrate in a compact millimeter-wave wireless communication system.