Frequency-controlled broadband and broad-angle beam scanning is proposed using a circular-patch array fed by planar spoof surface plasmon polaritons (SPPs). Here, a row of circularly metallic patches is placed near an ultrathin planar spoof SPP waveguide. When the SPP wave is transmitted through the waveguide, the circular patches are fed at the same time. Because of the phase difference fed to the patches, the proposed structure can realize wide-angle beam scanning from backward direction to forward direction as the frequency changes, breaking the limit of traditional leaky-wave antennas. Both numerical simulations and measured results demonstrate good performance of the proposed structure. It is shown that the scanning angle can reach 55° with an average gain level of 9.8 dBi. The proposed frequency scanning patch array is of great value in planar integrated communication systems.

Frequency-Controlled Broad-Angle Beam Scanning of Patch Array Fed by Spoof Surface Plasmon Polaritons

Advances in modern technology have aided the development of a class of miniaturized satellites called SmallSats that typically weigh less than 500 kg. Key members of this family are CubeSats. CubeSats can weigh as little as 1.33 kg, with a typical volume of 10 ? 10 ? 10 cm3. Their potential has motivated the scientific community to revisit existing spacecraft technologies to make them suitable for CubeSats.

For Satellites, Think Small, Dream Big: A review of recent antenna developments for CubeSats.

This paper aims to design, fabricate, and analyze transparent and flexible monopole antennas for an application in wearable glasses. A multilayer electrode film composed of 100-nm-thick indium–zinc–tin oxide (IZTO)/Ag/IZTO (IAI), a type of transparent conducting oxide electrodes, is selected as the conductors of antennas and ground planes of the wearable glasses. The average transparency of the proposed antennas is measured to be 81.1% in the visible wavelength, and the electrical conductivity of the proposed antennas is measured to be 2 000 000 S/m. The proposed antennas are fabricated with physical vapor deposition process in high vacuum. Moreover, nontransparent antennas made of a 40-nm-thick silver (Ag) thin film are designed and fabricated to compare their performances with the transparent IAI antennas. To reduce the electromagnetic field absorption of the human head, we introduced and analyzed three configurations (types A–C) of monopole antennas having different directions of radiation patterns. The fabricated IAI antennas show the average efficiency of 40% and 4-dBi peak gain at 2.4–2.5 GHz. Furthermore, they have a specific absorption rate lower than 1.6 W/kg, which complies with the Federal Communications Commission standard, when the input power is 15 dBm, which is Google Glass’s.

Transparent and Flexible Antenna for Wearable Glasses Applications

A novel transparent ultra-wideband antenna for photovoltaic solar-panel integration and RF energy harvesting is proposed in this paper. Since the approval by the Federal Communications Committee (FCC) in 2002, much research has been undertaken on UWB technology, especially for wireless communications. However, in the last decade, UWB has also been proposed as a power harvester. In this paper, a transparent cone-top-tapered slot antenna covering the frequency range from 2.2 to 12.1 GHz is designed and fabricated to provide UWB communications whilst integrated onto solar panels as well as harvest electromagnetic waves from free space and convert them into electrical energy. The antenna when sandwiched between an a-Si solar panel and glass is able to demonstrate a quasi omni-directional pattern that is characteristic of a UWB. The antenna when connected to a 2.55-GHz rectifier is able to produce 18-mV dc in free space and 4.4-mV dc on glass for an input power of 10 dBm at a distance of 5 cm. Although the antenna presented in this paper is a UWB antenna, only an operating range of 2.49 to 2.58 GHz for power scavenging is possible due to the limitation of the narrowband rectifier used for the study.

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A Novel Transparent UWB Antenna for Photovoltaic Solar Panel Integration and RF Energy Harvesting

In this paper, antennas made out of transparent conducting oxides (TCOs) are explored The optical transparency of transparent conducting oxides is achieved through thin-film depositions on substrates However, thin-film depositions create a new set of electrical challenges that require a full understanding of semiconductor physics This work looks into the governing equations that limit light transmission, absorption, and reflection through a transparent conductor, along with the electrical conductivity and antenna efficiency of transparent-conducting-oxide thin-film patch antennas

Challenges with Optically Transparent Patch Antennas

A circularly polarized meshed patch antenna design is presented. The proposed antenna consists of two square meshed patches, which generate two orthogonal linear polarizations at two slightly different frequencies. A common proximity feedline is utilized to excite the two patches, and a 90 ° phase difference can be achieved between the two resonant frequencies, which is needed for circular polarization. The overall structure of this antenna is highly compatible with solar panels; thus, it is of great significance for small satellite applications. The measured results of the antenna prototype show that it has a 3-dB axial-ratio (AR) bandwidth of 15 MHz, a 10-dB impedance bandwidth of 2%, and a gain of 5.15 dB at its center frequency 2.47 GHz.

Circularly Polarized Meshed Patch Antenna for Small Satellite Application

Properties of optically transparent patch antennas designed from meshed conductor and transparent conductive films are studied and compared. It is shown that at S band, meshed antenna provides the best antenna efficiency for the highest transparency. It is practical to design a 90% transparent meshed antenna with more than 60% transparency. Indium tin oxide (ITO) films, although less visible to human eyes than conductive meshes, at an optical transparency of 80%, provide an antenna efficiency of less than 30% at 2.5 GHz. AgHT (silver coated polyester film) film has lower transparency compared to ITO films for the same antenna efficiency. It is also shown that with the progress in material processing, the efficiency of an ITO patch antenna can be improved to be comparable to a meshed one. In addition, one can improve the efficiency of an antenna designed from ITO films by increasing the operational frequency.

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A comparative study on two types of transparent patch antennas

A study on the efficiency of transparent patch antennas designed from indium tin oxide (ITO) films is presented to provide design guidelines for patch type transparent antennas. The trade-offs between optical transparency and antenna efficiency is analyzed by considering typical material properties of ITO films. It is shown that the efficiency of a patch antenna designed from ITO films is determined by the electron mobility of ITO films, operational frequency, and the substrate material. The study shows that with today's material processing methods, it is feasible to achieve at least 30% efficiency of an ITO antenna with 90% optical transparency for operational frequency higher than 5 GHz. While progress in material science may improve the antenna performance, the highly transparent patch antenna with 30% efficiency may be employed in array design for practical implementations.

A study on the efficiency of transparent patch antennas designed from conductive oxide films

This letter presents an impedance bandwidth enhancement method for optically transparent meshed patch antennas using a coplanar proximity feed. The antenna design is potentially compatible with solar panel integration. The proposed antenna consists of three meshed patch elements with slightly different sizes, resulting in an improved impedance bandwidth that is approximately 2.5 times as wide as that of a single-element meshed patch antenna.

Bandwidth Enhancement of Meshed Patch Antennas Through Proximity Coupling

There is a growing interest in optically transparent antennas. Turpin et al. has demonstrated a meshed patch antenna with 93% transparency where the antenna could be either fabricated from electroformed metal mesh or screen printed on transparent substrates with conductive inks [1]. For a faster and more accurate fabrication, it is favorable to print antenna with an inkjet printer as described by Rida [2]. While Rida's approach focused mainly on using paper substrates and on ring or dipole type antennas, this paper is aimed to present a cheaper printing method and the feasibility of printing patch type antennas on transparent substrates for the applications such as solar cell integration.

Tursunjan Yasin

Papers

Circularly Polarized Meshed Patch Antenna for Small Satellite Application

A comparative study on two types of transparent patch antennas

A study on the efficiency of transparent patch antennas designed from conductive oxide films

Bandwidth Enhancement of Meshed Patch Antennas Through Proximity Coupling

Inkjet printed patch antennas on transparent substrates