Integrated Antenna Research Articles

Compact Dual-Polarized Shared-Dipole Antennas for Base Station Applications

Crossed-dipole (CD) antennas have been widely employed for dual polarization in wireless communication systems in recent years. In this paper, a novel design concept of dual-polarized shared-dipole (DPSD) antenna is presented. Different from the traditional CD antennas, the arms of the DPSD antenna are shared for two orthogonal polarizations. This design technique leads to significant size reduction and high isolation compared to the traditional CD antennas. The operation principle of the proposed antenna is theoretically analyzed. To validate the presented design concept, two novel DPSD antennas are designed, fabricated, and measured. The first design is a four-port DPSD antenna, which is a straightforward demonstration of the operation principle of the DPSD antenna. The second design is a highly integrated DPSD antenna, which avoids the use of a feed network and provides a simple configuration to design the dual-polarized antenna. Both of the DPSD antennas are designed to operate at 1.7–2.7 GHz for base station applications. The simulated and measured results confirm that the two DPSD antennas have wide bandwidth with VSWR 35 dB dB. In addition, stable gain and half-power beamwidth are obtained with the variance less than ±0.55 dB and ±3.5°, respectively.

2-D Scanning Magnetoelectric Dipole Antenna Array Fed by RGW Butler Matrix

In this paper, a 2-D scanning magnetoelectric (ME) dipole antenna array fed by printed ridge gap waveguide (PRGW) Butler matrix is proposed. The ME dipole antenna is designed to achieve a bandwidth wider than 20% at 30 GHz and stable gain of 6.5 ± 0.8 dB over the operating frequency bandwidth. A $4\times 4$ planar PRGW Butler matrix is designed and constructed using a four PRGW hybrid couplers having a wide bandwidth performance. The overall performance of the Butler matrix exhibits about 5° phase error over the operating frequency bandwidth. The integration of ME dipole antennas with the designed Butler matrix results in four fixed beams, one in each quadrant at an elevation angle of 35° from the broadside to the array axis. The proposed passive beam switching network (BSN) has a wide bandwidth of 20% with radiation efficiency higher than 84% over the operating bandwidth. The proposed BSN shows a stable radiation pattern with a stable gain of 10.3±0.2 dB, where the sidelobe level is less than −15 dB over the whole operating frequency band. The fabricated prototype of the proposed BSN is tested, where the measured and simulated results show an excellent agreement.

Dual-band System composed by a Photonics-based Radar and a Focal-Point/Cassegrain Parabolic Antenna

This work reports a dual-band radar system composed of aphotonics-based transceiver and a unique dual-band antenna. The proposed antenna consists of an integration of conventional focal-point and Cassegrain parabolic antennas in the same structure, ensured by using a subreflector based on a frequency selective surface. Numerical and experimental results in terms of the antenna reflection coefficient, radiation pattern and gain are reported with excellent agreement over both frequency ranges. The innovative dual-band photonics-based radar transceiver operates simultaneously in the S- and X-bands. The radar system has been properlyvalidated by multiple detections of helicopters and airplanes in real conditions.

Phase- and Amplitude-Control Metasurfaces for Antenna Main-Lobe and Sidelobe Manipulations

The metasurface (MS) antenna is an important microwave component in the communication system due to its unique beam radiation capability. However, current studies mainly pay attention to improve the performance of the main lobe of the MS antenna, leaving the sidelobe unexplored although it is also essential in some practical applications. In this paper, several phase- and amplitude-control reflected MSs have been proposed to simultaneously manipulate the antenna’s main lobe and sidelobes. The MSs consist of modified I-shaped particles which can independently manipulate the phases and amplitudes of the cross-polarization waves by changing the split size and orientation, respectively. A focusing phase distribution and different Taylor amplitude distributions have been fixed on the MSs. By illuminating the MSs with a self-made antenna, we have successfully designed four MS antennas. For the first antenna, we solely pay attention to improve the main lobe and achieve a high gain of 20.7 dB at 10 GHz. For the other three antennas, we also aim to manipulate their sidelobes. The resultant sidelobe levels (SLLs) are about −25 dB in the $xoz$ plane for the second antenna, −29 dB in the $yoz$ plane for the third antenna, and both of the former two characteristics for the fourth antenna. Compared with the first MS antenna, the last three antennas suffer from gain reductions of 2, 1.7, and 3 dB, respectively. These proposed MS antennas provide a new way to manipulate both main-lobe levels and SLLs and also greatly promote the integration of MSs and antennas.

Optical slot antennas and their applications to photonic devices

Abstract We present optical slot antennas and their applications to photonic devices. We show that metallic nanoslots have the properties of a slot antenna by measuring the transmission spectra and far-field radiation patterns and then prove that they can be physically regarded as magnetic dipoles in the optical region. Additionally, we can generate directional radiations from optical slot antennas by adopting the geometry of radiofrequency Yagi-Uda antenna and properly adding auxiliary elements called reflectors and directors to a single slot antenna. We present two cases as the applications of optical slot antennas. One is the integration of slot antennas to plasmonic waveguides. This combination can be used as a basic unit for optical interconnection to free space and plasmonic via in multilayered plasmonic structures. The other is the integration of slot antennas to the electrode of light-emitting diodes (LEDs). Using slot antennas, we can control the polarization and direction of emissions from LEDs. Besides the above-mentioned two cases, we expect that optical slot antennas have possible applications to various photonic devices and can be essential elements in future integrated photonic circuits with nanometer scales.

Compact planar active integrated inverted‐F antenna with frequency reconfigurable capability

This study presents two compact high-efficiency active integrated antennas (AIAs) working at 2.15 GHz. Both AIAs are realised by integrating the planar inverted-F antenna (PIFA) at the back side of the class-E power amplifier. In the first design, the antenna input impedance is transformed into an optimum impedance of the power amplifier. It achieves the maximum power added efficiency (PAE) of 68.6% with a total dimension of 0.36λ0 × 0.32λ0 × 0.03λ0 (λ0 is calculated at 2.15 GHz). In the second design, the antenna directly connected to the drain terminal of the power amplifier and offers a maximum PAE of 74% with a compact size of 0.21λ0 × 0.17λ0 × 0.04λ0, results in the size reduction of 59%. The novelty of the second design is it offers frequency reconfigurable nature by moving the shorting plate of PIFA without scaling the power amplifier and antenna, which can support Universal Mobile Telecommunications System (UMTS) (1920–2170 MHz), long term evolution (LTE)-40 (2300–2400), and Worldwide Interoperability for Microwave Access (WiMAX) (2500–2690 MHz) frequency bands. The measured results demonstrate that the proposed reconfigurable AIA yields the maximum PAE of 64% at both frequencies 2.3 and 2.6 GHz.

Polarization agile self‐oscillating active integrated antenna for spatial modulation wireless communications

AbstractThis article proposes a new design concept of active integrated array antennas having oscillation and modulation functions for spatial modulation wireless communication systems. Several configurations of the active integrated array antennas are proposed and discussed. The proposed active integrated antennas provide polarization modulated radio waves with a simple structure. A polarization switchable ring‐slot active integrated antenna employing Gunn oscillators is designed and experimentally demonstrated as an example of the proposed concept. The prototype active integrated antenna successfully switched its polarization angle between ±45°. The proposed active integrated antenna concept was found to be feasible.

Inkjet Printing of Wideband Stacked Microstrip Patch Array Antenna on Ultrathin Flexible Substrates

This paper presents a bandwidth-enhanced, low-cost, compact, inkjet-printed multilayer microstrip fractal patch antenna for integration into flexible and conformal devices. The antenna consists of two layers of patches, with the first layer inkjet-printed directly on a 0.125-mm (only 0.005 of the operating wavelength) Kapton polyimide substrate. On top of it, a 0.12-mm-thick SU-8 polymer is covered. To achieve the desired miniaturization and good impedance match, a Minkowski fractal geometry patch is employed as the second layer inkjet-printed on top of the SU-8 polymer. The proposed antenna has compact dimensions of only <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$22\times 31$ </tex-math></inline-formula> mm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> and covers 4.79–5.04-GHz frequency spectrum with <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$S_{11} &lt; -10$ </tex-math></inline-formula> dB. Moreover, a 2-bit <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$1\times 4$ </tex-math></inline-formula> phased array antenna (PAA) is constructed, and its scan ability is estimated to demonstrate its potential application in the true-time-delay flexible PAA systems. The prototype is fabricated and tested for impedance and radiation characteristics. The measured and the simulation results show the superiority of the proposed antenna.

Self-Oscillating Active Integrated Antenna With Harmonic Suppression Using Metamaterial Resonators and Ground Radiation

A self-oscillating active integrated antenna (AIA) with harmonic suppression using metamaterial resonators and ground radiation is proposed and investigated. Two composite right-/left-handed (CRLH) cells are connected in parallel and operated at negative first-order mode as the left-handed resonators to serve as the frequency selective element and the feedback path of the oscillating circuit at the same time. Meanwhile, the radiation parameters are independently controlled by exciting dipole-like ground-mode radiation using the CRLH cells. Benefiting from the high-quality factor of the CRLH cells and the newly added harmonic choking filters, the proposed AIA shows extraordinarily low phase noise, along with notable radiation parameters and good dc-to-RF conversion efficiency. The design principle, linear and nonlinear simulated data, and experimental results are carefully discussed and validated.

Integration of Wireless Coil and Bluetooth Antenna for High Charging and Radiation Efficiencies

In this paper, a wireless charging coil integrated with a Bluetooth antenna is proposed. The equivalent circuit model is developed to analyze this multifunctional coil. The outermost turn of the coil is appropriately designed in order to improve the radiation efficiency of the antenna. In this way, the radiation frequency of the coil is determined by the length of the outermost coil. Meanwhile, the inductance of the coil is adjusted to achieve high charging efficiency. When the coil is taken as a Bluetooth antenna, the measured reflection coefficient has achieved a fractional bandwidth of 8.3%, covering a frequency range of 2.3–2.5 GHz, with $\vert {S} _{11}\vert dB. The measured radiation efficiency of the antenna is about 62% at 2.4 GHz. When the coil is applied, the system charging efficiency is about 61%. In particular, the entire circuit module is fabricated on the low-cost FR4 printed circuit board. It can be expected that both the radiation and charging efficiencies can further be improved by using low-loss substrate.

The effect of a metamaterial-based wearable microstrip patch antenna on the human body

Body-worn communication devices have attracted much attention due to their wide applications. In this regard, various wearable antennas that have lots of advantages have been designed by researchers in recent years. Metamaterials that have negative refractive index can also be used in the wearable antenna designs because they have an ability to eliminate harmful health effects. In this study, a metamaterial-based wearable microstrip patch textile antenna operating in industrial, scientific, and medical bands was designed and simulated. The radiation values of this antenna were analyzed. Then metamaterial-based electromagnetic band gap (EBG) structure and wearable antenna integration was designed. Two different integrated antenna designs (3 × 3 and 5 × 3) were proposed. We obtained the performances of these antenna designs and calculated the specific absorption rate (SAR) values. We calculated the absorbed power 48.8, 0.167, and 0.0485 W/kg for 10 g tissue of wearable microstrip patch antenna, EBG integrated wearable antenna with 3 × 3 design, and EBG integrated wearable antenna with 5 × 3 design, respectively. Because the SAR values of the EBG integrated wearable antenna designs are well below the standard values, we can say that the designs proposed in the study can be used in many areas, such as military, health monitoring, and wireless communication.

Design of Compact Single-Layer Textile MIMO Antenna for Wearable Applications

A compact single-layer textile MIMO antenna is designed for wearable applications. The theory of characteristic mode is used to guide the antenna design and analyze its performance. The MIMO antenna utilizes a small ground plane as the main radiator, which is capacitively loaded by two strips along two orthogonal edges. The whole system occupies a volume of 38.1 mm $\times38.1$ mm $\times2$ mm, with each antenna having a dipole-like radiation pattern of linear polarization. Good isolation of above 12 dB is achieved due to the quasi-orthogonal radiations generated by the two antennas, providing pattern and polarization diversities. The envelope correlation coefficient between the antennas is below 0.01. The proposed antenna, fabricated on a flexible felt with a permittivity of 1.2, has a wide bandwidth of 20%. Due to its broadband behavior, the antennas remain well matched at the target band when worn on the body and bended. The loss of the human tissue results in the drop of the antenna gains to 1.6 dBi and 1.2 dBi, respectively, for the two antennas. The proposed antenna is competitive for wearable applications, due to its compact size, single-layer structure, easy integration, robustness, and reasonable on-body antenna gain.

Waveguide excitation and collection of surface-enhanced Raman scattering from a single plasmonic antenna

Abstract The integration of plasmonic antennas on single-mode silicon nitride waveguides offers great perspective for integrated surface-enhanced Raman spectroscopy (SERS). However, the few reported experimental demonstrations still require multiple plasmonic antennas to obtain a detectable SERS spectrum. Here, we show, for the first time, SERS signal detection by a single nanoplasmonic antenna integrated on a single-mode SiN waveguide. For this purpose, we investigated a backscattering detection scheme in combination with background noise reduction, which allowed an optimization of the signal-to-noise ratio (SNR) of this platform. Furthermore, a comparison with the free-space SERS spectrum of the same antenna shows that the conversion efficiency from pump power to total radiated Stokes power is twice as efficient in the case of waveguide excitation. As such, we explored several important aspects in the optimization of on-chip SERS sensors and experimentally demonstrated the power of exciting nanoplasmonic antennas using the evanescent field of a waveguide. This observation not only is useful for Raman sensing but also could be beneficial for any process involving plasmonic enhancement.

A Dual-Functional Triple-Mode Cavity Resonator With the Integration of Filters and Antennas

A novel concept for the two-in-one design with the integration of filters and antennas, using a single cavity, is presented in this communication. Basically, a triple-mode resonator (TMR) is utilized as a common feeder to achieve filtering and radiating functions at three different frequency bands. Each of the three bands adopts one of the three fundamental modes, namely, TE <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">011</sub> , TE <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">101</sub> , and TM <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">110</sub> , in a single TMR to realize the relevant functions. Owing to the modal orthogonality of these fundamental modes, high isolation can be effectively realized among these three channels. Based on the proposed TMR, three different prototypes are designed for different applications. For the first prototype, the structure of a dual-band filter plus an antenna is presented using a second-order TMR. Based on the combination of a duplexer plus an antenna, the second prototype is attained. To further explore the function of the proposed TMR, the structure of a filter plus a dual-polarization antenna is depicted as the third prototype. For verification, the third prototype is fabricated and tested. Good agreement between the simulated and the measured results is achieved, which proves the feasibility of the proposed design methodology.

A Wearable Self-Injection-Locked Sensor With Active Integrated Antenna and Differentiator-Based Envelope Detector for Vital-Sign Detection From Chest Wall and Wrist

This paper presents a new wearable self-injection-locked sensor with a self-oscillating active integrated antenna (AIA) and a differentiator-based envelope detector for detecting vital signs from the chest wall and the wrist. The AIA is designed to radiate the electromagnetic signal and sense the scattered-back signal, which is phase modulated by the physiological movement of the human chest and wrist. The received self-injection signal from the subject under test locks the AIA and simultaneously introduces a variation in the output magnitude (amplitude modulation) and a shift in the oscillation frequency (frequency modulation). In other words, the output signal of the AIA is a frequency-modulated carrier with an amplitude-varying envelope. To acquire the vital signs from the modulated signal, an envelope detector is integrated with a microwave differentiator to form a differentiator-based envelope detector, which demodulates signal. The heartbeat and wrist pulse rates measured by the proposed sensor agree well with the results acquired by a finger pulse oximeter. Since the proposed demodulator has a simple architecture, it has a potential to be integrated with the AIA in a multilayered printed-circuit board for the realization of a compact wearable self-injection-locked radar sensor.

Circularly polarised rectangular microstrip antenna design with arbitrary input impedance

This study describes two stand-alone iterative algorithms that fully solve the issue of generating non-standard input impedances in probe-fed circularly polarised rectangular microstrip antennas (CPRMA). Both were derived from a new cavity model-based methodology that controls, at the frequency of operation ( f o ), the input reactance and resistance levels without disturbing the circular polarisation (CP) characteristics of the antenna. The first algorithm finds the antenna dimensions and probe position for an arbitrarily selectable input impedance and the second algorithm determines the possible choices of input impedance for a given dielectric substrate and f o . To highlight the applicability of both algorithms, two prototypes were designed and built: a right-hand CP (RHCP) active antenna with input impedance Z A = 34.17 + 40.34 i Ω , and an RHCP reference antenna (RA) with input impedance Z RA = 50 + 0 i Ω . These antennas were utilised in the design and characterisation of a co-designed global positioning system active integrated antenna. The experimental and theoretical results show excellent agreement.

Integration Concept of the Reflectometry Diagnostic for the Main Plasma in DEMO

This paper presents the initial conceptual study of integration of reflectometry antennas and waveguides (WGs) in DEMO. The antennas are located at several poloidal angular positions covering a full poloidal section of the helium-cooled lithium lead breading blanket. The concept of slim cassette (SC) is presented which allows for possible side attachment to the blanket sector and offers compatibility with remote handling (RH) operations. The proposed concepts for WGs sectors relative motion decoupling, vacuum boundary breaking, and RH are presented. Monte Carlo neutronic simulations have been done in order to evaluate the heat loads and shielding capabilities of the system. The first results indicate that the cooling for the EUROFER diagnostic components (antennas and WGs) can in principle be provided by the blanket cooling services (He is considered) via connection to the main back supporting structure and routed via the main diagnostic structure body. The first results on the SC thermal analysis indicate that for the first wall (FW), an increase of He speed is required (or a higher cooling volume) as temperatures are above blanket FW temperature. As for the inner components (shielding and wave guides), the cooling requires localized optimization (hot spots in module corners and front antennas) but respects average temperature limit requirements.

A Novel Configuration of a Microstrip Microwave Wideband Power Amplifier for Wireless Application

RF/microwave power amplifier (PA) is one of the components that has a large effect on the overall performance of communication system especially in transmitter system and their design is decided by the parameters of transistor selected. This letter presents a new concept of a wide-band microwave amplifier using scattering parameters that is often used in the radio frequency communication systemas an application of the active integrated antenna[1- 2]. This power amplifier operates from 1.75 GHz to 2.15GHz frequency and it is based on AT-41410 NPN transistor that has a high transition frequency of 10GHz. The proposed Single Stage PA is designed by microstrip technology and simulated with Advanced Design System (ADS) software. The simulation results indicate good performances; the small power gain (S21) is changed between 11.8 and 10dB. For the input reflection coefficient (S11) is varied between -11 and -22.5dB. Regarding the output reflection coefficient (S22) is varied between -13.1 and -18.7dB over the wide frequency band of 1.75-2.15GHz and stability without oscillating over a wide range of frequencies.

Multiband, frequency reconfigurable, and metamaterial antennas design techniques: Present and future research directions

In recent years, the demand for multifunctional components has increased tremendously. Advancement in integrated technology has provided researchers with ample capability to fit diversified applications operating at different frequencies in one wireless device. Integration of multiband antennas in conjunction with frequency reconfigurability offers an optimal antenna design. In addition, the incorporation of metamaterials yields controllable and promising radiation properties. This paper contributes uniquely to the field of antenna design in two ways. First, it provides the domain and technical aspects associated with multiband, frequency reconfigurable, and metamaterial antennas. Second, it provides a critical review of literature. The paper additionally highlights the deficiencies in the design techniques reported in the literature.

Design of penta‐band antenna with integrated LNA circuit for vehicular communications

In this study, the design of concurrent penta-band capable antenna with integrated low-noise amplifier (LNA) for vehicular wireless communication applications is presented. Spiral structured penta-band-based planar monopole antenna is designed to cover navigational frequencies 1.2 and 1.5 GHz, wireless communication frequencies 2.4 and 3.3 GHz and dedicated short range communication frequency 5.8 GHz. LNA was designed and developed with pseudomorphic high electron mobility transistor technology, frequency transformation technique, and load-pull methodology that operates simultaneously at all desired frequencies. The designed antenna with integrated LNA helps better return loss and improved impedance bandwidth compared with passive antenna designs. The developed antenna module operates simultaneously at 1.2, 1.5, 2.4, 3.3, and 5.8 GHz with a gain >10 dB and noise figure <;2 dB. More than 150 MHz impedance bandwidth achieved at all the desired bands with this proposed integrated antenna module with LNA.