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This study provides the design and demonstration of a Ku/K band horn‐fed linear polarization (LP) to circular polarization (CP) converter using a reflectarray antenna based on the holographic technique and the generalized law of total reflection without any iterative algorithms. The proposed hologram performs wide‐range frequency beam scanning with minimum gain losses and cross‐polarization levels. It comprises 2,500 diagonal slotted octagonal subwavelength metasurfaces with a periodicity of 0.266λ0 = 4 mm at 20 GHz as the center frequency. Two equations are defined to compute Y11 of the proposed unit cell regarding its dimensions for TE(0,0) and TM(0,0) Floquet modes. They significantly simplify the coding procedure and reduce the computational time for synthesizing the hologram. The antenna is simulated using the CST software from 14 to 25 GHz. As a confirmation, a prototype is manufactured and measured at 16, 18, 20, 22, and 24 GHz to verify its performance. The simulated and measured results are well‐matched. The presented hologram achieves 40% 1.8‐dB axial ratio (AR) bandwidth (16–25 GHz), 40% 3.3‐dB gain bandwidth (16–24 GHz), and above 30% 2‐dB gain bandwidth (16–22 GHz). Moreover, the antenna can perform beam scanning from 42° to 24° by changing the frequency from 16 to 24 GHz with peak gain values greater than 20.33 dBi. The LHCP pencil beams are at least 24° off‐broadside, so the proposed hologram avoids the feed blockage. These achievements make the hologram one of the best candidates for satellite communications, radar applications, short‐range communication, and point‐to‐point communication. Key Points: The antenna is designed based on the holographic technique and the law of total reflection for Ku and K band applicationsThe antenna frequency scans its main LHCP beam in a wide range with a high gain and low lossThe antenna performs LP to LHCP conversions with a wide axial ratio bandwidth and low cross‐polarization levels [ABSTRACT FROM AUTHOR]

This letter shows experimentally the realization of a high-gain multibeam bidirectional radiation in a wide frequency range via a planar holographic leaky-wave structure where the beams can scan from backward to forward direction as the frequency varies from 12 to 18 GHz. To realize these two key features, i.e., wideband characteristic and bidirectional multiple-beam pattern, we exploit the characteristic of a wideband surface wave launcher and inherent nature of a metasurface supporting TE mode at the same time. In more detail, this antenna benefits from a TE-mode antipodal Vivaldi as a distinguished feed, which has a broadband behavior, on a surface without metallic ground plane and realizes a high-gain bidirectional multibeam pattern. A four-beam linearly polarized antenna, including two backward and broadside beams in front side and two backward and broadside beams in the back side of the antenna is designed, fabricated, and tested at 12 GHz. The measured gain, sidelobe level, cross polarization, efficiency, and 3 dB bandwidth of the gain, are 17.8 dBi, −17 dB, −30 dB, 26.5%, and 43.3%, respectively, which are great achievements. Moreover, the maximum scan angle of $\text{44}^\circ $ , i.e., from $({\boldsymbol{\theta },\boldsymbol{\varphi }}) = ({\text{30}^\circ,180})\ $ to $({\boldsymbol{\theta },\boldsymbol{\varphi }}) = ({\text{14}^\circ,\text{0}^\circ})$ , is achieved for the backward beams when the frequency varies from f = 12 GHz to f = 18 GHz. [ABSTRACT FROM AUTHOR]

A multibeam radiator with each beam possessing independent polarization is developed by a single-feed holographic reflectarray (RA) antenna without using any optimization algorithms. Regardless of wave polarization, the relation between the electromagnetic properties of the antenna aperture (henceforth referred to as “hologram”) and impinging wave properties can be described by the holographic technique. For the practical implementation of such a hologram, we used a subwavelength metallic patch with anisotropic properties to satisfy the input admittance distribution of the hologram. In doing so, a fast numerical method, fundamentally inspired by the method of moments, is employed to calculate the input admittance of the element for all angles of incidence. This technique significantly speeds up the design process. Finally, as a typical case, a simple circularly polarized RA with four-beam radiation pattern was manufactured and tested at 13 GHz. The measured results showed that the aperture efficiency of 45.8%, cross-polarization discrimination of higher than 25 dB, 1 dB drop gain, 3 dB axial ratio bandwidths of 19.23% and 18.26%, sidelobe level of below −17 dB, and peak gain of around 19.43 dBi for each beam were obtained. [ABSTRACT FROM AUTHOR]

In this paper, a novel systematic method based on the holographic theory to design a reflectarray (RA) antenna is presented. According to the holographic technique, one can record features of electromagnetic waves impinging on a specific surface and then, whenever needed, reconstruct each of them. We exploit this property to design a single-feed RA with a multibeam linearly polarized pattern without using any iterative method such as optimization algorithms in the design process. At first, various kinds of interferograms along with related input admittance distributions are introduced according to the polarization and number of radiated beams. Afterward, a simple subwavelength metallic patch as a scalar admittance unit cell is employed to implement the input admittance distribution of the interferograms. Moreover, a fast analytical method, which is fundamentally inspired by the method of moments, has been employed to calculate the input admittance of the utilized element. Finally, as a typical case, an 18 cm $\times $ 18 cm linearly polarized RA with a two-beam radiation pattern has been manufactured and tested at 15 GHz. The sidelobe level, cross-pol, and efficiency of the antenna are found −26 dB, lower than −10 dB, and 47.2%, respectively, which meet the expectations. [ABSTRACT FROM AUTHOR]

A three-dimensional complete bandgap (CBG) in the visible range is achieved by a self-similar spherical photonic crystal (PC) fabricated using the materials with low refractive index. A novel holographic technique is developed to fabricate such a structure. A CBG with a width of 120 nm is obtained experimentally. Even though the light not passing through the center of the sphere incidents on the PC with an incident angle of 49, a 30-nm-wide CBG can still be kept. Theoretical analysis is also given in which experimental results can be well explained. [ABSTRACT FROM PUBLISHER]

We present results that demonstrate the active management of eight ~100-GHz-spaced wavelength-division-multiplexed (WDM) channels using a polarization-insensitive spatial-light-modulator-based holographic filter. The filter has a fundamental stepping resolution close to 25 GHz and 3-dB width of each individual passband equal to 42 GHz. Arbitrary permutations of dropped and passed channels are possible. Additionally, passed channels can be transmitted according to an equal-amplitude comb filter function or be transmitted with weighted-amplitude passbands to effect power equalization where necessary. The holographic technique is further extendable to passband spectral engineering, yielding near-rectangular “top hat” passbands. Suppression of the dropped channels, which is consistently >15 dB in these experiments, can be straightforwardly improved by deploying a spatial light modulator of greater resolution and higher pixel number. The technology has potential application as the key element in both an optical add-drop multiplexer and a dynamic multichannel equalizer. The passband 3-dB width can be straightforwardly reduced to allow processing of multiple channels at the 50-GHz spacing of future WDM systems [ABSTRACT FROM PUBLISHER]