Transparent Antenna Research Articles

Optically Transparent Honeycomb Mesh Antenna Integrated into OLED Light Source

The co-integration of antennas with lighting sources appears as an effective way to distribute broadband networks closer to users, lowering interference and transmitted power, as well as to reduce energy consumption in future lighting systems. We here present an original contribution to the implementation of transparent and invisible antennas with OLED light sources. To validate the proposed approach, the honeycomb mesh technique was used, and an optical transparency of 75.4% was reached. The transparent mesh antenna was compared with the non-transparent full-metal antenna in terms of radio-electrical parameters. Our prototype was designed using copper films deposited on a glass substrate. The simulation results of the S-parameters and the radiation patterns were validated against measurements performed in an anechoic chamber. The directivity and gain obtained were 6.67 dBi and 4.86 dBi at 5.16GHz, respectively. To study the effect of antenna integration with OLEDs, optical and photometric characterizations with and without the antenna were measured, and the colorimetric parameters were then treated using the IES TM-30-18 standard.

Broadband High Optical Transparent Intelligent Metasurface for Adaptive Electromagnetic Wave Manipulation.

Intelligent metasurfaces have garnered widespread attention owing to their properties of sensing electromagnetic (EM) environments and multifunctional adaptive EM wave manipulation. However, intelligent metasurfaces with broadband high optical transparency have not been studied to date, and most of the previous intelligent metasurfaces lack an integrated design for their actuators and sensors, resulting in lower integration levels. This study proposes a novel intelligent metasurface with adaptive EM wave manipulation ability and high optical transparency from visible to infrared bands. This metasurface consists of a transparent and current-controlled reconfigurable metasurface as an actuator by integrating patterned vanadium dioxide (VO2) into metal-meshed resonant units, transparent broadband microstrip antenna as a sensor, recognition-and-feedback module, and actuator- and sensor-integrated design on the same substrate. The EM-regulating capability of the designed transparent intelligent metasurface is theoretically analyzed using the coupled mode theory, and a prototype metasurface device is fabricated for experimental verification. Simulation and experimental results demonstrate that the metasurface exhibits over 80% normalized transmittance from 380 to 5,000 nm and adaptive EM wave manipulation (reflective strong shielding function with a shielding efficiency of over 24 dB, high transmittance function with a transmission loss of 1.24 dB, and strong absorption function with an absorption of 97%) according to the EM wave power parameters without manual intervention. This study provides an avenue for transparent intelligent metasurfaces with extensive application prospects in areas such as intelligent optical windows, radar enclosures, and communication.

Design consideration and recent developments in flexible, transparent and wearable antenna technology: A review

AbstractThe wearable technology and flexible electronics have been convoluted in modern technologies and many of applications especially insensors, biomedical, displays, solar panels, glasses, smart cities, integrated circuits, and wireless body area network (WBAN). They offer capability of mechanical deformation conditions mainly stretchable, bendable, foldable features and capable to severe environmental conditions. Nowadays, a device having lightweight, low‐profile, compact in size and flexible deployment on the system platforms is preferred. With the flexibility in the design of the antenna, they require flexible, robust, easy to wear, visually imperceptible, unobtrusiveness, and planar material for the realization. The characteristics of the wearable antenna may vary according to the material conductivity and their optical transparency, substrate selection and their thickness along with permittivity opted for and mechanical deformation behavior. Generally, the textile material is utilized to design the flexible wearable antenna due to material flexibility which can minimize the losses and enhance the antenna performance. Conversely, the visually imperceptible and flexible material is utilized to design transparent wearable antenna due to appropriate trade‐off between conductivity and optical transparency of the materials. For diverse WBAN applications, the flexible, transparent, and wearable antennas are utilized. This paper elaborates the comprehensive review and the state‐of‐the‐art research on the diverse categories of the wearable antennas based on the substrate characteristics such as flexibility and transparency. In addition, it provides the broad investigation of the flexible and transparent materials utilized to design wearable antennas and different tissue layers with their dielectric properties to develop the human multilayer phantom model.

Optically transparent dual-band antenna for UHF and S-band applications

This paper presents a novel optically transparent antenna that utilizes Indium Tin Oxide-coated Polyethylene Terephthalate (ITO-PET) and Soda-lime-glass (SLG) substrate. It explores ITO-PET and SLG for transparent antenna fabrication, thoroughly evaluating the antenna’s performance in relation to ITO-PET’s conductivity. Operating in dual bands (1.6–2 GHz UHF and 3.25–4.95 GHz S-band), the antenna’s inventive design features a slotted circular structure with a modified ground plane, crucial for achieving dual-band functionality. Despite ITO-PET’s relatively low conductivity, the antenna outperforms expectations, exhibiting a wider bandwidth in the higher band and positive gain in both bands, conforming the potential of ITO-PET. The successful realization of this innovative concept is validated through the fabrication and measurement of the antenna prototype, signaling a new frontier in transparent antenna technology.

Design and optimization of a transparent and flexible MIMO antenna for compact IoT and 5G applications

This work presents an optically transparent and flexible MIMO antenna that features two square patch elements placed in close proximity, aiming to meet the demands of compactness, flexibility, optical transparency, and visual appeal for IoT applications and future 5G wireless communication. The design includes a simple offset fed configuration to achieve the required isolation and impedance matching. It simplifies the process of creating closely spaced transparent MIMO antenna configurations. By optimizing and analyzing this structure, the antenna achieves better isolation and diversity gain performance, even when the patch elements are positioned very close to each other. To achieve optical transparency and flexibility, the antenna uses thin polyethylene terephthalate (PET) material as a substrate, which is a thermoplastic polymer resin from the polyester family. The wired metal mesh parameters for conducting parts of the MIMO antenna and offset position of the feed are carefully optimized to achieve required optical transparency, isolation, impedance matching and radiation performance without any complex decoupling or impedance matching network.

Selection of metallic liquid in sub-6 GHz antenna design for 6G networks

The rapid evolution of wireless communication systems toward 6G demands efficient antennas with the features of adaptability and versatility. Liquid antennas have gained significant research interest due to their unique features in realizing small, flexible, transparent, and reconfigurable antennas for promising applications in future wireless systems. In this paper, in order to find a suitable metallic liquid for effective antennas, we design and compare the performance of metallic liquid antennas using Mercury, gallium indium alloy (EGaIn), and Graphene metallic liquid in the sub-6 GHz frequency. The antenna is realized by the metallic liquid in a poly methyl methacrylate microfluidic channel over a liquid crystal polymer substrate at 5.6 GHz frequency. The performance of these metallic liquid antennas is analyzed by their electromagnetic and radiation performance. The Graphene-based metallic liquid antenna shows better electromagnetic performance in comparison to Mercury and EGaIn metallic liquid antennas.

Autonomous low-energy communication module based on inkjet-printed transparent antenna

Autonomous low-energy communication module based on inkjet-printed transparent antenna

An optically transparent coplanar L-probe fed antenna based on capacitively coupled array of patches

An optically transparent antenna fed by a coplanar L-probe is proposed in this paper. Indium-doped tin oxide (ITO) with a sheet resistance of 3.5 Ω/sq etched on a soda-lime glass substrate is used as radiation array and ground to achieve high optical transmittance. TM 10 and TM 20 modes are excited simultaneously to expand work bandwidth. The fabricated antenna achieves a –10 dB reflection bandwidth of 27.5% from 4.7 to 6.2 GHz with the overall size of 42 mm × 42 mm × 3.3 mm. Different from many antennas composed of ITO, the proposed antenna exhibits directional radiation patterns with the maximum realized gain of 4.6 dBi and the maximum efficiency of 61%. Meanwhile, the optical transmittance of the antenna can reach above 58%.

A Low-Cost Microfluidic and Optically Transparent Water Antenna with Frequency-Tuning Characteristics.

In this study, a novel microfluidic frequency reconfigurable and optically transparent water antenna is designed using three-dimensional (3D) printing technology. The proposed antenna consists of three distinct parts, including a circularly shaped distilled water ground, a sea water-based circular segmented radiator, and a circularly shaped distilled water-based load, all ingeniously constructed from transparent resin material. The presented antenna is excited by a disk-loaded probe. The frequency of the antenna can be easily tuned by filling and emptying/evacuating sea water from the multisegmented radiator. The radiator consists of three segments with different radii, and each segment has a different resonant frequency. When the radiator is filled, the antenna resonates at the frequency of the segment that is filled. When all the radiator segments are filled, the antenna operates at the resonant frequency of 2.4 GHz and possesses an impedance bandwidth of 1.05 GHz (40%) in the range of 2.10-3.15 GHz. By filling different radiator segments, the frequency could be tuned from 2.4 to 2.6 GHz. In addition to the frequency-switching characteristics, the proposed antenna exhibits high simulated radiation efficiency (with a peak performance reaching 95%) and attains a maximum realized gain of 3.8 dBi at 2.9 GHz. The proposed antenna integrates water as its predominant constituent, which is easily available, thereby achieving cost-effectiveness, compactness, and transparency characteristics; it also has the potential to be utilized in future applications, involving transparent and flexible electronics.

Quad-port multiservice integrated optically transparent automotive antenna for vehicular classification applications

The demand for vehicular antennas increases in tandem with the need for multiple features in automobiles. The development of optically transparent antenna (OTA) has made it possible to deploy antennas on delicate surfaces such as glass. Earlier studies on OTA demonstrated its viability using materials such as transparent conducting oxides (TCO) and conductive polymers. A tri-band OTA is proposed in this paper for vehicular applications. The antenna operates at 1.8 GHz, 2.4 GHz and 3.39–12 GHz bands, covering automotive/wireless applications such as GSM, Bluetooth, Wi-Fi, vehicular communication and electronic toll collection. The proposed OTA is developed on soda lime glass, and the material TCO is used for the radiator and the ground plane. The antenna prototype is tested on windshield and in an anechoic chamber, the gain and efficiency are found to be greater than 1 dBi and 80%, respectively. Furthermore, a machine learning technique for vehicle classification is proposed, which could help in electronic toll collection, automatic vehicle identifier, and parking management applications. The presented algorithm achieves 80% classification accuracy with a minimum window size.

Dual-Polarized Conformal Transparent Antenna Array With Hemispherical Beam Coverage

Dual-Polarized Conformal Transparent Antenna Array With Hemispherical Beam Coverage

RETRACTED ARTICLE: A novel traffic load balancing approach for scheduling of optical transparent antennas (OTAs) on mobile terminals

RETRACTED ARTICLE: A novel traffic load balancing approach for scheduling of optical transparent antennas (OTAs) on mobile terminals

A flexible and transparent pliers shaped antenna for ultra-wideband applications

Flexible transparent antennas have broad potential applications in wireless communication and RF energy harvesting, providing visualization, small size, and integration functions for electronic devices. The use of optically transparent materials is an essential direction in the development of flexible transparent antennas. In this paper, a flexible and transparent antenna is designed by indium tin oxide material and photolithography process, which is suitable for wideband communication field. The broadband characteristics of the antenna are realized by using irregular slots and rectangular microstrip lines on the ground plane. The antenna operates in the frequency range of 1.73–20 GHz with a relative bandwidth of 168%, which is suitable for ultra-wideband (UWB) applications. The antenna has a compact structure and the relative size of 0.33 λ 0 × 0.28 λ 0. The measured results of the antenna are in good agreement with the simulated results, and the bending and folding tests show that the antenna has good mechanical flexibility and can cover the surface of irregular objects. This pliers-shaped antenna is applicable to a variety of UWB and wireless applications, such as LTE, Wi Max, 5G network, IoT, WIFI, mobile phone keys, and mobile payment.

Dual-Polarized Transparent Antenna and Its Application for Capsule Endoscopy System

In this paper, we proposed a small transparent thin film antenna for a wireless capsule endoscopy system. The transparent thin film antenna is needed to provide a clear 360° broad-sight view of the wireless capsule system in the future. Furthermore, the transparent thin film is critical for performing the dual-polarized antenna operating at 2.45 GHz. The proposed transparent thin film uses the nano-alignment process to further achieve low resistivity from 3.78 × 10−4 Ω-cm to 9.14 × 10−5 Ω-cm and improves the transparency by over 70%. The nano-alignment process includes periodic electrodes with AC signals that can effectively rearrange the nano-material into an ordered arrangement, enhancing the thin film’s microwave characteristics. Due to applying to the capsule endoscopy system, the ability of water resistance is also considered in this design. Therefore, the O2 plasma treatment is used to improve the water contact angle from 76° to 31°, measured on the surface of the thin film. The proposed transparent antenna is designed to have a center frequency of 2.45 GHz, a bandwidth of 855 MHz, and an antenna gain of −26.3 dBi, and is helpful for capsule endoscopy systems.

Design and fabrication of a super-wideband transparent antenna implanted on a solar cell substrate

In this study, an antenna with transparent super wideband CPW technology has been designed and built with the combination of solar panels for use in wireless communication equipment and systems that require mobile power. The transparency value of the antenna is 63.3%, which is an acceptable value for the optimal use of sunlight. The proposed antenna was designed and measured on a plexi-glass substrate with a dielectric constant of {{varvec{upvarepsilon}}}_{{varvec{r}}}=4.4 and various thicknesses, the proposed antenna was designed and measured. The copper sheet has a high electrical conductivity and therefore it was selected for the antenna's radiating component as compared to earlier techniques that employed metal oxide. All simulations were done with CST microwave studio software and frequency domain solver. The results indicated that the antenna's operating frequency ranges from 2 to 32 GHz. The results of the computations indicated that the antenna's peak gain and peak efficiency are 8.1 dB and 90%, respectively. Various multiple-input and multiple-output (MIMO) performance parameters, including the envelope correlation coefficient (ECC), diversity gain (DG), average effective gain (MEG), total active reflection coefficient (TARC), and channel capacity loss (CCL), were analyzed to demonstrate the antenna's performance.

Optically Transparent MIMO Antenna with Polarisation Diversity for Vehicular Communications

ABSTRACT A unique multiple-input-multiple-output (MIMO) adaptive intelligent antenna for vehicular communications is addressed in this article. It has a high degree of transparency that can be integrated with the windscreen for intelligent vehicular communications. The proposed diversity antenna has four monopole radiators oriented in orthogonal directions to obtain polarisation diversity. The optically transparent nature is realised using a soda-lime substratum of size 50 × 50 mm2 coated with Transparent Conductive Oxides (TCO). The Aluminium Zinc Oxide (AZO) is sputtered on top of a Fluorine Tin Oxide (FTO) to enhance the material’s conductivity with dual-conductive layer. The fabricated MIMO antenna has a bandwidth of 10 GHz and functions in the entire UWB range (2 to 12 GHz). By incorporating concentric circles into the ground, high confinement between nearly located antenna elements is achieved. The antenna has a peak gain of 2.9 dBi as measured. The Envelope Correlation Coefficient (ECC) of the antenna in the entire Ultra-wideband (UWB) region attributed to the TCO material shows a very low correlation among the antenna elements. Because of diversity gain of the proposed vehicular antenna is ˃ 9.8 dB, it can also operate with low transmission power. The findings indicate that the antenna is pertinent for current intelligent vehicles that require multiple communications without aesthetic hindrance.

64‐3: Invited Paper: Latest Developments Liquid Crystals for RF Applications

Driven by the need for new affordable wireless data communication technologies, special liquid crystals have been developed and optimized for use in microwave components above 10 GHz. As tunable dielectrics, they pave the way for continuously tunable antennas for SATCOM and wireless 5G/6G applications either fixed at home or on‐the‐move. This presentation gives an insight into the current material development with special focus on the application in transparent antennas for fixed 5G access. Sunlight stability tests for an equivalent device lifetime of 5 years were conducted resulting in yellowing index values of < 4, being 2.5 times less than the required threshold.

A Transparent Antenna Using Metal Mesh for UWB MIMO Applications

This paper presents a transparent ultra-wideband (UWB) multiple-input multiple-output (MIMO) antenna based on a wired metal mesh (MM) structure. Transparent antennas (TAs) can be integrated on various building materials with little visual impact to facilitate flexible massive indoor wireless device deployment. The proposed antenna achieves 77% transparency by hollowing out both metal and substrate into a mesh shape, while maintaining more than 83% radiation efficiency. The MIMO antenna consists of 4 elements, each being a co-planar waveguide (CPW) fed UWB monopole and adjacent elements being placed orthogonally to produce dual polarisation. The operating band of the MIMO antenna spans over 3.2-11.2 GHz. A parasitic decoupling structure aligned with the mesh grid is designed to enhance the isolation between MIMO elements without degrading the transparency. Within the entire operating band, the isolation between any two elements is more than 20 dB. The peak gain varies from 3.3 dBi to 7.2 dBi within the bandwidth. The envelop correlation coefficient (ECC) is less than 0.004. The channel capacity and time domain response are analysed. The antenna can be easily fabricated by conventional PCB and laser cutting techniques with a low cost.

Compact, Flexible and Transparent Antenna Using MMF for Conformal Wi-Fi 7 Applications

Compact, Flexible and Transparent Antenna Using MMF for Conformal Wi-Fi 7 Applications

Optically Transparent MIMO Antenna with Polarization Diversity

An Optically transparent UWB antenna with polarization diversity for the use of automotive communications is presented in this paper. The novel two element antenna operates at the frequency range of 2.5-8 GHz with dimension 45×45 mm2 and peak gain 1.2 dBi. Antenna elements are placed orthogonally to achieve polarisation diversity. The proposed antenna is placed on a soda lime glass substrate which has a permittivity of 7.3 and thickness of 2.2 mm. The radiator of the antenna is made of FTO with sheet resistance 6 Ω/sq. The Diversity gain of the proposed antenna is greater than 9.9 and ECC value is lesser than 0.02 for the frequency range of 3-8 GHz. The isolation between the antenna elements is more than 15 dB without any complex decoupling structures between them.