Showing papers on "Conformal antenna published in 2017"
TL;DR: This paper provides an overview of the existing multibeam antenna technologies which include the passiveMultibeam antennas (MBAs) based on quasi-optical components and beamforming circuits, multibeams phased-array antennas enabled by various phase-shifting methods, and digital MBAs with different system architectures.
Abstract: With the demanding system requirements for the fifth-generation (5G) wireless communications and the severe spectrum shortage at conventional cellular frequencies, multibeam antenna systems operating in the millimeter-wave frequency bands have attracted a lot of research interest and have been actively investigated. They represent the key antenna technology for supporting a high data transmission rate, an improved signal-to-interference-plus-noise ratio, an increased spectral and energy efficiency, and versatile beam shaping, thereby holding a great promise in serving as the critical infrastructure for enabling beamforming and massive multiple-input multiple-output (MIMO) that boost the 5G. This paper provides an overview of the existing multibeam antenna technologies which include the passive multibeam antennas (MBAs) based on quasi-optical components and beamforming circuits, multibeam phased-array antennas enabled by various phase-shifting methods, and digital MBAs with different system architectures. Specifically, their principles of operation, design, and implementation, as well as a number of illustrative application examples are reviewed. Finally, the suitability of these MBAs for the future 5G massive MIMO wireless systems as well as the associated challenges is discussed.
737 citations
TL;DR: Nan et al. as mentioned in this paper developed acoustically actuated antennas that couple the acoustic resonance of the antenna with the electromagnetic wave, reducing the antenna footprint by up to 100. And they demonstrated 1-2 orders of magnitude miniaturization over state-of-the-art compact antennas without performance degradation.
Abstract: State-of-the-art compact antennas rely on electromagnetic wave resonance, which leads to antenna sizes that are comparable to the electromagnetic wavelength. As a result, antennas typically have a size greater than one-tenth of the wavelength, and further miniaturization of antennas has been an open challenge for decades. Here we report on acoustically actuated nanomechanical magnetoelectric (ME) antennas with a suspended ferromagnetic/piezoelectric thin-film heterostructure. These ME antennas receive and transmit electromagnetic waves through the ME effect at their acoustic resonance frequencies. The bulk acoustic waves in ME antennas stimulate magnetization oscillations of the ferromagnetic thin film, which results in the radiation of electromagnetic waves. Vice versa, these antennas sense the magnetic fields of electromagnetic waves, giving a piezoelectric voltage output. The ME antennas (with sizes as small as one-thousandth of a wavelength) demonstrates 1–2 orders of magnitude miniaturization over state-of-the-art compact antennas without performance degradation. These ME antennas have potential implications for portable wireless communication systems. The miniaturization of antennas beyond a wavelength is limited by designs which rely on electromagnetic resonances. Here, Nan et al. have developed acoustically actuated antennas that couple the acoustic resonance of the antenna with the electromagnetic wave, reducing the antenna footprint by up to 100.
241 citations
TL;DR: In this paper, a new concept that is called array-antenna decoupling surface (ADS) for reducing the mutual coupling between antenna elements in a large-scale array antenna is proposed for the first time.
Abstract: Massive multiple-input multiple-output (M-MIMO) technology is considered to be a key enabling technology for future wireless communication systems. One of the challenges in effectively implementing an advanced precoding scheme to a large-scale array antenna is how to reduce the mutual coupling among antenna elements. In this paper, a new concept that is called array-antenna decoupling surface (ADS) for reducing the mutual coupling between antenna elements in a large-scale array antenna is proposed for the first time. An ADS is a thin surface that is composed of a plurality of electrical small metal patches and is placed in front of the array antenna. The partially diffracted waves from the ADS can be controlled to cancel the unwanted coupled waves. Two practical design examples are given to illustrate the design process and considerations, and to demonstrate the usefulness of ADS for the applications of phased array antennas and M-MIMO systems when commonly used precoding schemes are applied. The attractive features of ADS include its applicability to a large-scale array antenna; suitability for a wide range of antenna forms; wide decoupling bandwidth; and simplicity in implementation.
238 citations
TL;DR: In this article, a wearable flexible reconfigurable folded slot antenna is presented, where the antenna is composed of a folded slot and a stub where the reconfigurability is achieved by turning a p-i-n diode on and off, which alters the radiation characteristics of the stub.
Abstract: This letter presents a wearable flexible reconfigurable folded slot antenna. The antenna is composed of a folded slot and a stub where the reconfigurability is achieved by turning a p-i-n diode on and off , which alters the radiation characteristics of the stub. The operating frequency and polarization of the slot and stub are different. Hence, a polarization-dependent dual-band artificial magnetic conductor (AMC) surface is integrated with the antenna to improve its radiation performance and to reduce the specific absorption rate (SAR). The antenna is designed and fabricated on a flexible substrate, and its performance is measured for both flat and curved configurations. The measurements show an excellent agreement with the simulations. To examine its performance as a wearable antenna, it is measured on a human body. Simulations show that the SAR level is reduced when the AMC surface is used as an isolator. The proposed wearable antenna structure can be used for wireless body area network (WBAN) and Worldwide Interoperability for Microwave Access (WiMAX) body-worn wireless devices.
130 citations
TL;DR: In this article, a multiband conformal antenna for implantable as well as ingestible devices is presented, which has the following three bands: medical implanted communication service (MICS: 402-405 MHz), the midfield band (1.45-1.6 GHz), and the industrial, scientific and medical band (ISM: 2.4-2.45 GHz).
Abstract: This paper presents a multiband conformal antenna for implantable as well as ingestible devices. The proposed antenna has the following three bands: medical implanted communication service (MICS: 402–405 MHz), the midfield band (1.45–1.6 GHz), and the industrial, scientific, and medical band (ISM: 2.4–2.45 GHz) for telemetry or wireless monitoring, wireless power transfer (WPT), and power conservation, respectively. A T-shaped ground slot is used to tune the antenna, and this antenna is wrapped inside a printed 3-D capsule prototype to demonstrate its applicability in different biomedical devices. Initially, the performance of the proposed antenna was measured in an American Society for Testing and Materials phantom containing a porcine heart in the MICS band for an implantable case. Furthermore, to stretch the scope of the suggested antenna to ingestible devices, the antenna performance was simulated and measured using a minced pork muscle in the ISM band. A modified version of the midfield power transfer method was incorporated to replicate the idea of WPT within the implantable 3-D printed capsule. Moreover, a near-field plate (NFP) was employed to control the leakage of power from the WPT transmitter. From the simulation and measurements, we found that use of a ground slot in the implantable antenna can improve antenna performance and can also reduce the specific absorption rate. Furthermore, by including the NFP with the midfield WPT transmitter system, unidirectional wireless power can be obtained and WPT efficiency can be increased.
103 citations
TL;DR: The design, fabrication, packaging, and performance characterization of a conformal helix antenna created on the outside of a capsule endoscope designed to operate at a carrier frequency of 433 MHz within human tissue is described.
Abstract: This paper describes the design, fabrication, packaging, and performance characterization of a conformal helix antenna created on the outside of a capsule endoscope designed to operate at a carrier frequency of 433 MHz within human tissue. Wireless data transfer was established between the integrated capsule system and an external receiver. The telemetry system was tested within a tissue phantom and in vivo porcine models. Two different types of transmission modes were tested. The first mode, replicating normal operating conditions, used data packets at a steady power level of 0 dBm, while the capsule was being withdrawn at a steady rate from the small intestine. The second mode, replicating the worst-case clinical scenario of capsule retention within the small bowel, sent data with stepwise increasing power levels of -10, 0, 6, and 10 dBm, with the capsule fixed in position. The temperature of the tissue surrounding the external antenna was monitored at all times using thermistors embedded within the capsule shell to observe potential safety issues. The recorded data showed, for both modes of operation, a low error transmission of 10-3 packet error rate and 10-5 bit error rate and no temperature increase of the tissue according to IEEE standards.
65 citations
TL;DR: It is argued that slot antennas are well suited for incorporation into capsule antennas for the present application and continue to maintain a stable impedance match even when a battery is added inside the capsule, or when there is a change in the battery size and/or its position.
Abstract: An ultrawideband conformal capsule slot antenna, which has a simple configuration and a stable impedance matching characteristic, is described in this paper. In the past, wideband outer-wall antennas have been proposed for capsule-type applications. However, this paper shows that the outer wall is not a good choice for placing capsule antennas, since such a choice exhibits a high specific absorption ratio, low gain, and low efficiency. Instead, the antenna proposed in this paper is conformal to the inner wall of a capsule shell, and it provides a wide impedance bandwidth ranging from 1.64 to 5.95 GHz (113.6%). Furthermore, the impedance matching remains stable even with a change in the operating environment. Since in a typical application scenario a capsule will move through the digestive system, and thus experience varying environments, a wide bandwidth and stable performance are both very desirable attributes of the antenna, whose design is discussed in this paper. Moreover, the proposed antenna continues to maintain a stable impedance match even when a battery is added inside the capsule, or when there is a change in the battery size and/or its position. Given these advantages, we argue that slot antennas are well suited for incorporation into capsule antennas for the present application.
63 citations
TL;DR: In this paper, a frequency and polarization-reconfigurable antenna using switching PIN diodes is presented, which is based on a center-fed circular cavity with switchable shorting vias along its outer edge.
Abstract: The principle and experimental validation of a frequency- and polarization-reconfigurable antenna using switching PIN diodes is presented in this letter. The antenna is based on a center-fed circular cavity with switchable shorting vias along its outer edge. Turning a set of shorting vias on on one side and off on the other side creates a radiating slot with controllable length and location along the side wall of the cavity that results in different antenna resonance frequencies and polarizations. As a proof of concept, a particular realization of the antenna is designed that can change the linear polarization in six different angles and at five discrete frequencies (spanning more than one octave). Based on the proposed concept, quasi-continuous frequency- and polarization-reconfiguration is feasible using individual control of a large number of switching devices.
62 citations
TL;DR: In this article, the authors present two conformal antenna designs that can be integrated with CubeSats' solar panels without competing for surface real estate: slot geometry and optically transparent patches placed on top of solar cells.
Abstract: This article reviews two conformal antenna designs that can be integrated with CubeSats' solar panels without competing for surface real estate. The first type of antenna is of slot geometry so that the antennas can be integrated around solar cells, and the second type is optically transparent patches that can be placed on top of solar cells. Detailed design philosophy, prototypes, measurements, and assessment of interaction between the antennas and solar cells are presented. As larger CubeSats have sufficient panel area to host antenna arrays, a subwavelength reflectarray, with optimal overall properties both in terms of gain and optical transparency, is presented. The overall transparency and aperture efficiency of the reflectarray are higher than 90% and 40%, respectively, making it a promising solution as a high-gain conformal CubeSat antenna.
62 citations
TL;DR: In this paper, the authors presented the theory, design, simulation, fabrication, and performance of a flexible dual-band MM absorber, which is resonant at microwave frequencies.
Abstract: This paper presents the theory, design, simulation, fabrication, and performance of a flexible dual-band MM absorber, which is resonant at microwave frequencies. The sandwich structure of the MM absorber is composed of the periodic array of the T-shaped metallic patches and a continuous metallic plane, which are separated by a middle flexible dielectric layer. The optimized geometric parameters were obtained by numerous simulations using the full wave finite integration technology of CST 2015. The simulated results indicate that the proposed MM absorber has two distinct absorption peaks at 16.77 and 30.92 GHz with the absorption ratio of 98.7% and 99.3%, respectively. The absorber has a thickness of 0.2403 mm, which is only 1/74 and 1/40 of the wavelength for the resonance frequency of 16.77 and 30.92 GHz. The influence of the material's properties and structural curvature on the absorption performance was investigated by numerous simulations. The proposed MM absorber is highly sensitive to the polarization of the incidence EM wave and has good absorption properties over a large range of the incidence angle for the incidence EM wave. The electric field and surface current distributions at two independent resonance frequencies were analyzed for providing insight into the EM wave absorption mechanism. Simulated results show that two different resonance modes are introduced into the single patterned metallic resonance structure to realize the dual-band performance. The laser ablation process was adopted to fabricate the sample of the proposed absorber. Measured results for the normally incident EM wave show an agreement with the simulated results. The fabricated MM absorber shows significant mechanical flexibility and can easily be conformed to the unusual surfaces such as cylindrical, pyramid, and spherical. Furthermore, this design concept can be extended to the other absorber structure and the other frequency bands, therefore, which can greatly enrich the applications in antenna, sensing, thermal image, and detection. For instance, in the design of projectile-borne conformal antenna array, a flexible ultrathin MM absorber can easily be loaded between the antenna and the projectile body to reduce the radiation interference, weaken the coupling loss, and reduce the RCS.
51 citations
TL;DR: In this paper, a dual-and-tri-band conformal capsule antennas with simple configuration is proposed by modifying the ground of the inverted-F antenna and shifting the feed point.
Abstract: Additional resonances are often introduced in an inverted-F antenna (IFA) by modifying the “F” structure, which typically makes the antenna both complex and bulky To mitigate this problem, novel dual-/tri-band conformal capsule antennas with simple configuration are proposed in this paper by modifying the ground of the IFA and shifting the feed point With these modifications, the IFA is miniaturized, and yet it is able to simultaneously cover the MedRadio band (401–406 MHz) and ISM bands (902–928 MHz and/or 24–25 GHz) The resulting configurations remain simple and compact despite the modifications, which is very desirable for conformal capsule type of applications Furthermore, the impedance matching characteristics of the proposed IFAs remain stable even when a battery is added inside the capsule and the size or the position of the battery is modified Moreover, the impedance matching of the antenna continues to remain stable even as its surrounding environment is changed The operating principle of the proposed dual-/tri-band IFAs is discussed in detail and parametric study is carried out to investigate the characteristics of the proposed antennas The results of this paper are expected to be helpful for designing multiband antennas in the future
TL;DR: In this article, the authors proposed an approach for the realization of three-dimensional flexible antennas based on the use of liquid metal and additive printing technologies, and demonstrated the performance of the antenna in several bent configurations and in presence of the human body.
Abstract: This letter proposes an approach for the realization of three-dimensional flexible antennas based on the use of liquid metal and additive printing technologies. As a representative example, a miniaturized inverted-F antenna (IFA) operating at 885 MHz and suitable for wearable applications is designed, realized, and measured. The antenna sensitivity to the bending is strongly reduced, thanks to the proposed structure. The performance of the antenna in several bent configurations and in presence of the human body has been evaluated.
TL;DR: In this paper, the reduction of the radar cross section (RCS) of the Vivaldi antenna is achieved by removing a portion of the metal from the radiator and implementing periodic slots adjacent to the radiating edge.
Abstract: In this communication, radar cross section (RCS) reduction of Vivaldi antenna is achieved with structural modifications. This is realized by removing a portion of the metal from the radiator and implementing periodic slots adjacent to the radiating edge. These slots reduce the perpendicular reflections from the radiator, which causes reduction of the monostatic RCS. The proposed Vivaldi antenna operates from 4 to 12 GHz with 10 dB additional RCS reduction when compared with the reference Vivaldi antenna. The prototype is fabricated and its performance is validated using measurements.
TL;DR: The system-level simulation results show that the 3D-MIMO with 64 antennas can significantly improve the performance with 56% and 147% gain on cell-average and cell-edge throughputs compared with 2D-DIMO, and the measurement in typical high-rise scenario shows that the3D- MIMO can significantly enhance the data rate of users located at higher floors due to the capability of flexible elevation beamforming.
Abstract: Exploiting multiple-input–multiple-output (MIMO) techniques by using massive antennas can significantly improve the capacity and reliability of wireless systems and has been considered as one key technique in future fifth-generation mobile communications system. Considering the limitation of antenna panel size, placing the massive antennas in 2-D grid is an effective way for its commercialization, which is termed as “3D-MIMO.” In this paper, we study the performance of 3D-MIMO with massive antennas by system-level simulation using practical assumption and 3-D channel model and test the 3D-MIMO in field trial with commercial terminal and networks. In addition, we compare the system-level simulation results and the field trial test measurements. Our system-level simulation results show that the 3D-MIMO with 64 antennas can significantly improve the performance with 56% and 147% gain on cell-average and cell-edge throughputs compared with 2D-MIMO. We perform field trial to test the 3D-MIMO, and the results verify its performance gain obtained by simulation. Furthermore, the measurement in typical high-rise scenario shows that the 3D-MIMO can significantly enhance the data rate of users located at higher floors due to the capability of flexible elevation beamforming.
TL;DR: A tapered slot antenna is a promising candidate as it has the ability to address the problems such as penetration depth and resolution imaging in GPR system due to its directional property, high gain and greater bandwidth operation, both in the lower and higher frequency range.
Abstract: This paper presents a comparative review study on ultra-wideband (UWB) antenna technology for Ground Penetrating Radar (GPR) applications. The proposed antenna designs for UWB ground penetrating radar include a bow-tie antennas, Vivaldi antennas, horn antennas, planar antennas, tapered slot antennas, dipole antennas, and spiral antennas. Furthermore a comprehensive study in terms of operating frequency range, gain and impedance bandwidth on each antenna is performed in order to select a suitable antenna structure to analyze it for GPR systems. Based on the design comparison, the antenna with a significant gain and enhanced bandwidth has been selected for future perspective to examine the penetration depth and resolution imaging, simultaneously suitable for GPR detection applications. Three different types of antennas are chosen to be more suitable from the final comparison which includes Vivaldi, horn and tapered slot antennas. On further analysis a tapered slot antenna is a promising candidate as it has the ability to address the problems such as penetration depth and resolution imaging in GPR system due to its directional property, high gain and greater bandwidth operation, both in the lower and higher frequency range.
TL;DR: The theory of cavity-backed metasurface antennas is explained, and frequency diverse imaging is demonstrated with a pair of these antennas.
Abstract: Frequency diversity antennas with spatially structured radiation patterns reduce the reliance on actively switched elements for beamforming which become increasingly expensive and impractical as frequency increases. As the quality factor Q of a frequency diverse antenna increases, the antenna samples more spatial structure as the number of unique radiated coded spatial patterns correspondingly increases. Antennas that combine hollow cavities and metamaterial apertures achieve both large fractional bandwidth, in excess of 40%, and a high Q of 1600, so that each antenna radiates over 640 unique coded patterns. As compared to switched active antennas, such a passive antenna replaces the 50 antennas and switches that would produce at most (50/2)2=625 unique patterns. Furthermore, the engineered metamaterial apertures enable a radiation efficiency exceeding 60% to be achieved in a single desired polarization. The theory of cavity-backed metasurface antennas is explained, and frequency diverse imaging is demonstrated with a pair of these antennas.
TL;DR: In this paper, a conical conformal shaped-beam substrate-integrated waveguide (SIW) array antenna is proposed to obtain the same propagation characteristics along the longitudinal direction.
Abstract: The analysis and design of a millimeter-wave conical conformal shaped-beam substrate-integrated waveguide (SIW) array antenna is demonstrated in this paper. After investigating the influence of the conical surface on the propagation characteristics of a conformal SIW, a modification for the width of a conical conformal SIW is proposed to obtain the same propagation characteristic along the longitudinal direction. This feature is indispensable to employ the classic equivalent circuit of a planar slot array antenna in the design of a conical conformal antenna. In this case, the design process of the conformal antenna can be simplified. An efficient and accurate model method of the conical conformal SIW antenna is presented as well. Then, a design process of the conical conformal SIW slot array antenna is introduced. Furthermore, to implement the transition between a conical surface and a cylindrical surface, a flexible SIWtransition is designed with a good impedance matching. Finally, two low sidelobe level (SLL) SIW conical conformal antennas with and without the flexible transitions are designed. Both of them have −28 dB SLLs in H-plane at the center frequency of 35 GHz.
TL;DR: An end-to-end BMI antenna system characterization is detailed in this paper for multichannel implanted neural recording applications and it is proved that the BMI antenna link could support up to 100 recording channels.
Abstract: Brain-machine interface (BMI) is a multidisciplinary field that has been recently developed in an attempt to help restore functionalities for paralyzed individuals. One of the key components for the implementation of a wireless BMI necessitates unique designs for both the internal brain and external head antennas. In this paper, we initially revisited the design of an optimized 1-mm3 implantable antenna transferring power and data with a reduced size low profile external reader antenna by utilizing radio-frequency identification (RFID)-inspired backscattering. Detailed computational assessments and specific absorption rate evaluations are performed. Prototypes were characterized in terms of link efficiency through a realized RFID link with up to −25 dB link efficiency. The noise analysis for antennas in biological systems was performed using two novel absorption-noise models. And finally a channel capacity estimation was performed, proving that the BMI antenna link could support up to 100 recording channels. An end-to-end BMI antenna system characterization is detailed in this paper for multichannel implanted neural recording applications.
01 Sep 2017
TL;DR: In this paper, a planar linear series-fed patch array (SFPA) antenna is designed for transmitters of MRR and all the receivers for 77GHz automotive radar application.
Abstract: Array antennas for 77GHz automotive radar application are designed and measured. Linear series-fed patch array (SFPA) antenna is designed for transmitters of middle range radar (MRR) and all the receivers. A planar SFPA based on the linear one and substrate integrated waveguide (SIW) feeding network is proposed for transmitter of long range radar (LRR), which can decline the radiation from feeding network itself. The array antennas are fabricated, both the performances with and without radome of these array antennas are measured. Good agreement between simulation and measurement has been achieved. They can be good candidates for 77GHz automotive application.
19 Mar 2017
TL;DR: In this paper, several UWB on-body slotted patch antenna models are assessed and discussed, and an optimized model has been manufactured by taking into account the dielectric properties of human tissues.
Abstract: One of the most relevant challenges of next generation in-body devices consists in enhancing the medical applications of wireless networks qualitatively. The current standard does not allow high data rate wireless connections between implanted nodes. UWB systems have been considered as a potential candidate for future in-body devices. To establish a proper link within UWB, antenna matching should be ensured within the frequency range of interest. Besides, a good wave penetration trough the biological tissues is totally essential. In this work, several UWB on-body slotted patch antenna models are assessed and discussed. According to the propagation medium, the on-body antenna designs have been miniaturized and optimized taking into account the dielectric properties of human tissues. After a thorough comparison between antenna models, an optimized model has been manufactured. Finally, the performance of the optimized antenna prototype has been assessed.
TL;DR: In this paper, a 12-element conical antenna array made of four linear subarrays regularly spaced by 90° is proposed in C-band for communication applications on high velocity flying platforms.
Abstract: A 12-element conical antenna array made of four linear subarrays regularly spaced by 90° is proposed in C-band for communication applications on high velocity flying platforms. The beam forming network is stacked below the radiating part, and allows steering the subarray beam of the conical array. The performance of the main building blocks is described in detail, both numerically and experimentally. The measured radiation characteristics of the phased array are in good agreement with the simulation results between 5 and 5.4 GHz for all configurations with beam pointing directions varying between 30° and 110° in the elevation plane.
TL;DR: In this paper, a solution for passive tags based on a normal-mode helical antenna was proposed as an alternative to bulky and/or expensive solutions that can be found in the literature.
Abstract: 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.
TL;DR: In this article, a direct-fed slot antenna with a low profile of 7 mm to the top edge of the metal cover for 2.4-/5.8-GHz WLAN operation is presented.
Abstract: The slot antenna has been utilized for some recent notebook computers on the market. The FR4 substrates are usually required to print the metal patterns for coupled-feeding the 2.4 GHz (2400–2484 MHz) slot and also for contributing the 5.2 GHz (5150–5350 MHz) and 5.8 GHz (5725–5825 MHz) bands. This communication presents a simple, direct-fed slot antenna with a low profile of 7 mm to the top edge of the metal cover for 2.4-/5.2-/5.8-GHz WLAN operation. The antenna design did not require any substrate and can be implemented directly in the metal cover of a notebook computer at low cost. The design comprised two parallel-connected, 0.5-wavelength-slot portions, formed in a linear structure of length 79 mm and constant width 2 mm, and fed by a common antenna feed port using a mini-coaxial cable. The larger slot generated a 0.5-wavelength resonant mode in the 2.4-GHz band and a 1-wavelength mode for 5.2-GHz operation. The smaller slot operated in a 0.5-wavelength resonant mode, which covered the 5.8-GHz band. With a matching inductor properly set in the slot, good input impedance over the 2.4-, 5.2-, and 5.8-GHz bands can be attained.
01 Jun 2017
TL;DR: In this article, the design and manufacturing of an X-band pyramid horn antenna using 3-D printer is studied with its experimental results, and the measurement results of the 3D printed antenna are also compared with the simulation results.
Abstract: Herein, design and manufacturing of an X-band pyramid horn antenna using 3-D printer is studied with its experimental results. X-band is used for the military purposes with the marine and satellite technology based on the geographic discovery. Horn antennas are especially very preferable in these applications since they can be built easily at the different types depending on their utilizations and provide low voltage standing wave ratios. This work is focused on a pyramid horn antenna design and its manufacturing method with 3-D printer technology. The measurement results of the 3-D printed antenna are also compared with the simulation results.
TL;DR: This study analyzes the conformal design requirements of the array antenna, as well as the prominent contradiction between the high resolution and wide swath of SAR, and develops a specific process of synthesising the antenna pattern.
Abstract: The synthetic aperture radar (SAR) system equipped on the hypersonic platform in the near space presents many advantages compared with the conventional airborne SAR. However, due to the complex aerodynamic configuration and flight characteristics of the hypersonic platform, the radar design is facing some new challenges. Taking into account the new features of the platform, in this study the authors analyse the conformal design requirements of the array antenna, as well as the prominent contradiction between the high resolution and wide swath of SAR. After establishing the model of the conformal array antenna and the space coordinate system of the far-field radiation, a specific process of synthesising the antenna pattern is given. Furthermore, the antenna mask templates of optimising the antenna pattern are generated based on the main performance measures of the SAR system, and the modified meta particle swarm optimisation algorithm is exploited to obtain the optimal excitation phase of each array element in synthesising the ultimate antenna pattern. Finally, simulation results verify the effectiveness of the method, where the performance of the optimised antenna pattern is evaluated numerically.
TL;DR: In this article, the influence of the radius of a cylindrical supporting structure on radiation properties of a conformal millimeter-wave antenna array was studied, and the results showed that conformal antenna structures allow achieving large angular coverage and may allow beam-steering implementations if switches are used to select between different arrays around a cyl-indrical support structure.
Abstract: In this paper, we study the influence of the radius of a cylindrical supporting structure on radiation properties of a conformal millimeter-wave antenna array. Bent antenna array structures on cylindrical surfaces may have important applications in future mobile devices. Small radii may be needed if the antenna is printed on the edges of mobile devices and in items which human beings are wearing, such as wrist watches, bracelets, and rings. The antenna under study consists of four linear series-fed arrays of four patch elements and is operating at 58.8 GHz with linear polarization. The antenna array is fabricated on polytetrafluoroethylene substrate with thickness of 127 µm due to its good plasticity properties, and low losses. Results for both planar and conformal antenna arrays show rather good agreement between simulation and measurements. The results show that conformal antenna structures allow achieving large angular coverage and may allow beam-steering implementations if switches are used to select between different arrays around a cylindrical supporting structure.
TL;DR: In this article, a conformal array antenna with a reconfigurable radiation pattern in the azimuth plane at Ku band is presented, where an eight-faced prism has been set as 3-D antenna structure.
Abstract: A conformal array antenna with a reconfigurable radiation pattern in the azimuth plane at Ku band is presented. An eight-faced prism has been set as 3-D antenna structure. The radiating element consists of a rectangular waveguide ended on a slotted cavity. A radial waveguide network (RWGN) fed by a symmetrically placed coaxial probe has been implemented to equally feed each radiating element obtaining an omnidirectional behavior in the azimuth plane. The insertion of several metallic tuning screws (TSs) provides a reconfiguration mechanism of the electric field distribution in the RWGN and modifies the conformal array antenna amplitude feeding. Eight different configurations generating directional radiation patterns can be tuned by means of the insertion of certain TSs. In addition, the symmetrical positioning of them allows performing a main beam scanning every 45° in the azimuth plane. Several prototypes have been manufactured and measured to experimentally validate the antenna performance. A total of 65 different radiation patterns have been experimentally obtained using the proposed TSs, which provides a simple, low-loss, and low-cost reconfigurability mechanism to the presented conformal array antenna.
TL;DR: In this article, a truncated circular cone slot array antenna that radiates a circularly polarized (CP) conical beam is presented, where quasi-perpendicular slots are cut into the outer conductor of the truncated cone.
Abstract: A truncated circular cone slot array antenna that radiates a circularly polarized (CP) conical beam is presented. The direction into which the conical beam radiates depends mainly on the tilt angle of the outer conductor as well as the proper arrangement of the positions of its two slot arrays. The CP property is realized by introducing quasi-perpendicular slots that are cut into the outer conductor of a truncated circular cone. To illustrate the performance characteristics of this CP conical beam antenna, the tilt angle is set to 45° and the beam angle is pointed at 45° from boresight within the operating band. A prototype was fabricated and tested. The measured results demonstrate that its −10 dB impedance bandwidth ( $\vert S_{{11}}{\rm{\vert \, dB) is 720 MHz, from 5.05 to 5.77 GHz; and its 3 dB axial-ratio (AR) bandwidth is 500 MHz, from 5.5 to 6.0 GHz. Its realized gain over this AR bandwidth ranges from 4.84 to 5.8 dB. The designed beam direction can be easily changed to meet specific application requirements. Moreover, it can be readily reconfigured to be a conformal antenna mounted on the top of a high-speed mobile platform.
TL;DR: A circularly conformal array antenna of double stacked microstrip patches is presented in two radiation versions: omnidirectional and electronically switched directive beam, suitable to many applications such as Worldwide Interoperability for Microwave Access, wireless local area network, unmanned aerial vehicles or direction finding.
Abstract: A circularly conformal array antenna of double stacked microstrip patches is presented in two radiation versions: omnidirectional and electronically switched directive beam. Every single element is disposed on an eight-faced regular prism structure built in 3D print technology. The omnidirectional pattern is achieved in the azimuth plane by using a microstrip uniform power divider to equally excite the circular antenna. The switched directive beam coverage is obtained by replacing the uniform power divider with an electronically switched power divider. Four switched beams of 90° angular separation are digitally configured. A fractional matching bandwidth of 17.2% has been measured for both omnidirectional and switched beam prototypes. The conformal antenna was entirely manufactured by using both printed circuit board and 3D printing technologies. Therefore, a very compact, low cost and light weight antenna design has been implemented, suitable to many applications such as Worldwide Interoperability for Microwave Access, wireless local area network, unmanned aerial vehicles or direction finding.
TL;DR: In this paper, a two-element conformal antenna for receiving the global positioning system L1, L2, and GLONASS L1 signals for precision artillery applications is presented.
Abstract: This letter presents a two-element conformal antenna for receiving the global positioning system L1, L2, and GLONASS L1 signals for precision artillery applications. The antenna consists of two stub-loaded shorted conformal patches fed by coaxial cables and a stripline power combiner. The patch is realized on a cylindrical polymer substrate wrapped around an artillery fuze body. Two patches are placed 180° apart and combined to realize an omnidirectional pattern. The fabricated antenna shows good Global Navigation Satellite System signal receiving performance.