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International audience; We present a photonically-excited antenna array at E-band for scanning by beam switching in wireless links. First, we discuss the proposed technique applied to photonic-enabled (sub)millimeter-wave transmitters. Next, we present the proposed solution; it consists of two sub-arrays of stacked patches as primary feeds of a Polytetrafluoroethylene (PTFE) lens, with one photodiode feeding each sub-array. To validate the assembly, the return loss and radiation patterns have been measured for one of the sub-arrays excited with a coplanar probe. In turn, the lens illuminated by one of the sub-arrays yields a directivity of 27 dBi. The radiation patterns measured for the transmitter module (including the lens) are in very good agreement with full-wave simulations, and they show that excitation of one of either sub-arrays allows beam switching between 2.7 with a beam crossover at 3 dB. Finally, we have tested the transmitter in a 0.6 m wireless link. Depending on the position of the detector and on which subarray is excited, we have accomplished 5 Gbps transmission for on-off-keying modulation and direct detection (BER = 1E11). The system constitutes an initial proof of photonic-assisted beam switching for mm-wave transmitters enabling broadband operation with a directive and switchable beam. IEEE

A novel fixed-frequency beam switchable dual-beam antenna array is presented, which consists five dual-beam leaky-wave antenna (LWA) elements designed on substrate integrated waveguide (SIW) and integrated together on a common substrate. The LWAs work on fundamental wave and -1th spatial harmonic wave simultaneously and excite two symmetrical radiation beams in forward and backward direction respectively. In order to realize beam switching, three voltage-driven radio frequency chip switches (CSW-RFs) are used and integrated behind the antenna aperture. Since the periodic slot in LWA causes open stopband at the operating frequency, so the staggered radius amplification of local vias in the via walls of SIW is performed to suppress the open stopband. In addition, electromagnetic band-gap (EBG) structures, capable of reducing coupling between neighboring antenna elements, are embedded in between LWAs. The proposed dual-beam antenna array with beam switching capability between ±35, ±45, ±55, ±65 and ±75 degrees at 28 GHz are simulated, fabricated and measured. Both analysis and measurement results show that the proposed antenna array exhibits an excellent performance, which can be used in fixed-frequency beam-switching millimeter wave communication.

Conférence virtuelle; International audience; We present a photonic transmitter at E-band for beam switching in mm-wave wireless links. First, we discuss the trade-offs between beam switching and beam steering with arrays of photonic transmitters. Then, the designed transmitter is presented; it includes two 2×2 sub-arrays of stacked patches fed independently by two photodiodes. The transmitter is placed at the focal plane of a PTFE lens to increase the overall gain. Excitation of either sub-array allows 1D beam witching between ±2.7º for accurate beam alignment or reconfigurable links.

International audience; This abstract describes the first design and assembly of a photonically-excited antenna at E-band for beam switching in millimeter-wave wireless links. The designed antenna consists of two arrays of stacked patches, with one photodiode feeding each array. The stacked patch provides an impedance bandwidth larger than 23 % and a stable radiation pattern over the E-band. The array is combined with a lens to increase the overall gain. Excitation of either patch array allows beam steering between ±2.7° for accurate beam alignment. © 2020 IEEE.

Beam coverage switching of sub-6 GHz massive MIMO antenna is presented using low-loss passive phase shifter. A single-bit phase shifter which minimizes the loss caused by series resistance of a switch is designed and integrated with antenna. The massive MIMO array is fabricated and measured to examine beam switching function while maintaining low-loss characteristics.

In this paper, we propose a reconfigurable metasurface antenna for beam switching applications. The reconfigurable metasurface is formed by uniformly distributed double-split square rings loaded with positive-intrinsic-negative (PIN) diodes for dual operations of a wave reflector and a wave director. Specifically, when the PIN diodes are forward biased, an epsilon-negative (ENG) metasurface is realized which reflects all incident waves with appropriate polarization; when the diodes are reverse biased, at the same operating frequency, a mu-near-zero (MNZ) metasurface is acquired which directs wave propagation. For excitation, a dipole radiator loaded with the same type of PIN diode is designed. Simulation and measurement results show good agreement and verify the beam switching functionality of the proposed metasurface antenna.

This study proposes a cylindrical conformal array antenna (CCAA) for fifth-generation (5G) micro base station applications. The CCAA is composed of five Chebyshev flexible linear array antennas (LAAs) with a circumferentially uniform arrangement on the cylindrical surface. The LAA with a logarithmic periodic arrangement is constructed by synthesizing the current amplitude distribution coefficients in elements with the Chebyshev method. The LAA with a half-power bandwidth (HPBW) wider than 76° (-8.41° to 38.58°) and a peak gain greater than 10 dBi is fabricated via the micro-electromechanical system process. Cost-performance analysis shows that five is the best number of linear arrays. To achieve omnidirectional switching scanning of the circumferential section, five LAAs wrapped on the cylindrical surface are individually excited by connecting a radio frequency semiconductor switch to the exciting ports of an eight-way power divider. Moreover, beam-switch scanning of the CCAA is measured with the aid of a standard anechoic chamber. The irradiated performance with low mutual coupling and high realized gain is verified to be irrelevant to the structural variation of various flexible experiments of LAAs wrapped around a cylindrical surface. The CCAA with beam-switch scanning operates at 26 GHz and belongs to the 5G millimeter-wave band. Results show the proposed antenna achieves omnidirectional scanning property in the H plane and has a HPBW of only 9.08° in the E plane. The performances of the CCAA present potential advantage in flexible terminal equipment wireless communication.

Power dividers are critical components for mm-wave applications. They are used in antenna feeding structures to provide the suitable excitation in the antenna array systems and deployed in microwave smart beam switching subsystems. In this article a dual gap wideband in-phase power divider is presented. The bandwidth starts at 19 and ends at 40 GHz. We are targeting with this design both the k and ka bands. The proposed design achieved a very deep matching level below −18 dB.

We report results based on millimeter wave vehicle-to-infrastructure (V2I) channel measurements carried out in an urban street environment, down-town Vienna, Austria. Signal to noise ratios (SNRs) have been acquired at 60 GHz with 100 MHz bandwidth. Two horn antennas were used on a moving transmitter vehicle: one horn emitted a beam towards the horizon and the second horn emitted an elevated beam at 15-degrees up-tilt. This configuration was chosen to assess the impact of beam elevation on V2I communication channel variability. The variability of the V2I channel is shown by density estimates of the channel transfer function magnitudes. The channel changes severely along the vehicle trajectory in an urban street scenario. Density estimates in the region with clear wide-angle view are bimodal and motivate a two-wave with diffuse power (TWDP) fading model for V2I communication with horizontal and elevated antenna beams. We compare three different strategies for beam switching: fixed, geometry-based, and SNR-based.

A design for beam-switching antennas is proposed in this study. A cylindrical cavity with a reconfigurable conformal slot array distributed evenly along the middle of its side wall is presented. The reconfigurable feature of the slots is achieved by placing a diode switch across each slot. An integrated bias scheme is introduced for the diode switches to activate and disable the slots. By properly selecting the dimensions for the cavity and the number of activated slots, the optimum values for the gain and front-to-back ratio (FBR) of the antenna can be obtained. The gain value is further increased by adding a skirt-like structure to both the top and bottom of the cavity. A design example is presented with the operating frequency set at 5.8 GHz. The conformal array comprises 24 slots to provide a 15° resolution for main beam switching. The simulation results indicate that the design can offer an antenna gain up to 8.62 dBi and a FBR above 10 dB. These results and the corresponding radiation patterns have gone through experimental verification, from which good agreement is observed.

For modern directional communication networks, there is a significant and growing need for advanced antenna array designs that combine the high gain and broadband performance together with the low-cost and lightweight characteristics. In this letter, the beam-switching characteristics of a new 4 × 8 right-hand circularly polarized long slot antenna (LSA) array were analyzed when fed by an 8 × 8 Butler matrix. The radiation characteristics were analyzed in terms of bandwidth, beamwidth, gain, cross polarization (x-pol), and axial ratio. Stable radiation patterns were obtained when the main beam directions were within the ±30° angle. The beam-switching LSA array has measured gain of 13.5 dBic and beamwidth of 15° with x-pol greater than 10 dB and axial ratio less than 6 dB. Comparative results with a 4 × 8 stacked patch antenna array are also included for reference.

An oscillating active integrated antenna (AIA) with a switchable pattern among sum or difference is reported here. The AIA design consists of a passive feedback network and an active device. A two‐port, two‐element patch array coupled electromagnetically through T‐shaped microstrip lines is integrated into the feedback path of the oscillator circuit. This two‐port network acts as a radiator and frequency‐selective network for the oscillator circuit. The proposed AIA can switch in two different radiation pattern states by using p‐i‐n diodes. In the difference pattern, oscillating AIA has a measured null depth of −19.86 dB from the peak. The measured phase noise for both patterns is better than −105.1 dBc/Hz at a 1‐MHz offset from the oscillation frequencies. The dc‐to‐RF efficiencies for both pattern states are better than 20%. The proposed design is suitable to cover the space in a more efficient manner by generating the pattern among broadside or conical.

In this paper, the design of a printed RGW crossover for mm-wave beam switching network is proposed. The proposed device can be considered a good candidate in the design of beam switching network as it has a low loss with a wide bandwidth. The simulated results of the proposed crossover show a 13% fractional bandwidth centered at 30 GHz with an impedance matching level less than −20 dB and isolation level less than −15 dB. In addition, the proposed design has an average transmission loss of 0.5 dB over the operating frequency band.

This article presents a novel beam switching antenna design for Small Cell applications. The proposed antenna comprises five dual-polarized dipole antenna sets, two RF switching circuit boards and one hardware control circuit board. The proposed antenna can provide wide operating band covering the 2300–2700 MHz band, and has 31 radiation pattern combinations at +45/−45° polarization individually and has dual RF ports to support 2 × 2 MIMO system. This antenna has a low profile of 76 mm, and the whole size is 200 × 200 × 76 mm3 that can easily mount on indoor ceiling.

The fifth generation (5G) wireless communications systems have brought a growing need for various antennas, electrically small and large, low-gain and large-gain, also at millimeter wavelengths, and in many cases with beam steering or switching capability. Frequencies of 28 GHz, 38 GHz, 58 GHz, 60 GHz, 71–86 GHz, 140–150 GHz, and some even higher window frequencies are of interest in 5G and subsequent generations. Different parts of the systems need different kinds of antennas. In this presentation, we discuss two antenna types that we have recently studied, namely high-gain lenses with beam switching capability and lower gain printed antennas that suit very well for mass production.

This paper presents a design of switched beam antenna using parasitic elements for back lobe reduction to reduce interference signals coming from back side. A single circular patch is used to switch main beam pattern. Beam switching is controlled by shorted and open circuit at the edges of the patch while back lobe is reduced by shorted and open circuit at the parasitic elements. There are eight difference directions of beam switching. The maximum gain of the proposed antenna is 7.62 dBi and maximum back lobe reduction is 4.28 dB when parasitic elements are used.

Most accelerator-based space radiation experiments have been performed with single ion beams at fixed energies. However, the space radiation environment consists of a wide variety of ion species with a continuous range of energies. Due to recent developments in beam switching technology implemented at the NASA Space Radiation Laboratory (NSRL) at Brookhaven National Laboratory (BNL), it is now possible to rapidly switch ion species and energies, allowing for the possibility to more realistically simulate the actual radiation environment found in space. The present paper discusses a variety of issues related to implementation of galactic cosmic ray (GCR) simulation at NSRL, especially for experiments in radiobiology. Advantages and disadvantages of different approaches to developing a GCR simulator are presented. In addition, issues common to both GCR simulation and single beam experiments are compared to issues unique to GCR simulation studies. A set of conclusions is presented as well as a discussion of the technical implementation of GCR simulation.

PMAS, the Potsdam Multi-Aperture Spectrophotometer, is a new integral field spectrograph in the optical, which is optimized for good transmission and high image quality from 350 nm to 1 μm. We present our plan to implement a CCD charge-shuffle mode to allow for beam switching with a very high degree of sky subtraction accuracy for faint object 3-D spectroscopy.

Fiber-fed spectrographs can now have throughputs equivalent to slit spectrographs. However, the sky subtraction accuracy that can be reached on such instruments has often been pinpointed as one of their major issues, in relation to difficulties in scattered light and flat-field corrections or throughput losses associated with fibers. Using technical time observations with FLAMES-GIRAFFE, two observing techniques, namely dual staring and cross beam switching modes, were tested and the resulting sky subtraction accuracy reached in both cases was quantified. Results indicate that an accuracy of 0.6% on the sky subtraction can be reached, provided that the cross beam switching mode is used. This is very encouraging regarding the detection of very faint sources with future fiber-fed spectrographs such as VLT/MOONS or E-ELT/MOSAIC.

We predict that in coupled waveguides with balanced gain and loss, featuring stationary PT-symmetric modes in the linear regime, nonlinearity results in symmetry breaking above a critical power threshold, leading to sharp beam switching.

The non ergodic behaviour of the CMB temperature fluctuations has been seen through the non null dispersion of the third and fourth order moments of this field. Beam switching techniques favour the ergodicity although the small area covered by the experiments unfavour it.

This is a study of the use of a dual-beam, dual-detector synchrotron radiation system for transvenous coronary angiography in a human subject. This system eliminates the need for rapid beam switching, increases X-ray fluence by a factor of about 2.5, and makes it possible to record high- and low-energy images simultaneously, thus excluding artifacts arising from time subtraction. Besides coronary angiography, it may be possible to image the vertebral-basilar arterial circulation with this system.

The proton engineering frontier project (PEFP) 100- MeV proton linac has two main beamline systems to extract and deliver the proton beam to the user. The one is designed to extract 20-MeV proton beams at the medium energy transport system of the linac and to deliver them to five target stations through a beam switching system. The other is able to extract 100-MeV proton beams at the end of the linac and to deliver them to another five target stations through a beam distribution system. We have completed the detailed beam optics designs of the beamline system and performed intensive error analyses to set the marginal limits of engineering errors of the beamline components by using a dedicated beam transport code. The paper presents the error analysis results of the PEFP beamline systems along with their characteristics and beam optics designs.

The design of a completely quasi-optical 1.5 mm aircraft radiometer receiver is discussed in detail. The radiometer beam switching is described as well as a reflection isolator utililizing a reciprocating mirror. A quasi-optical local oscillator injection system using a Folded Fabry-Perot resonator is described and receiver performance levels given.

PMAS is a versatile integral field spectrograph based on the principle of a fiber-coupled lens array type of IFU. The instrument was commissioned at the Calar Alto 3.5m Telescope in May 2001. PMAS is offered as a common user instrument at Calar Alto since 2002. However, it has remained flexible enough to be used as a testbed for new observing techniques. Since the instrument is sensitive in the wavelength range from 0.35 to 1 μm, it is being used to experiment with faint object 3D spectroscopy for a variety of objects in stellar and extragalactic astronomy. Among these experiments, we have implemented a nod-shuffle mode of operation, which is a beam switching technique to achieve a high degree of sky subtraction accuracy. We describe the technical details of the special solution found for PMAS and first results obtained in test observations of faint haloes of planetary nebulae.

We analyze interactions of (2+l)-dimensional parametric soli tons and demonstrate non-planar beam switching in a bulk χ(2) medium. This includes controllable soliton repulsion, spiralling, and fusion. Analytical model predicting results of the soliton scattering is also derived and verified by direct numerics.

Unwanted radiation emited by sources in the foreground and immediate environment of the detectors is much more important than what astronomers want to observe. The success or the failure of submillimeter observations depends mainly on the techniques used to remove this parasitic radiation and its fluctuations such as photon noise. We analyse with some detail the formation of photon noise in multimode instruments and show that the usual simplified equations may give significantly wrong results in practical cases. Other sources of fluctuations, such as the atmospheric noise, and the way used to partly remove them are also described.

We analyze the interactions of (2+1) -dimensional parametric solitons and demonstrate nonplanar beam switching in a bulk X((2)) medium, which includes controllable soliton repulsion, spiraling, and fusion. An analytical model predicting the results of the soliton scattering is derived and verified by direct numerics.

Very sensitive low-noise amplifiers designed to receive transmissions from spacecraft are not necessarily suitable receivers for radio astronomy. In the former case a good signalto- noise ratio is required so that high data rates can be achieved. In the latter the ratio of signal to noise power may be as low as 10-4 and the stability of receiver gain and that of ail sources of noise during long integration times become of equal importance.This paper describes a novel solution to the problem, which allowed important astronomy to be performed while the ruby maser receivers belonging to the European Space Agency were installed on the Parkes radio telescope for an extended period of time.

A beam propagation method is employed to analyze the characteristics of crossed optical waveguides and related switches, based on such crossed waveguides. The complex coupling properties of passive crossings are highlighted and general design guidelines for passive devices as well as for switches are given.

This facility report describes some details which so far have not been published and also some new features recently built in. In particular the ion source, the fast beam switching system, the stripper and the final detection system will be described. Performances and possible error sources are discussed, especially the fact that current dependent results are obtained. These effects are most likely related to beam size variations which are caused by space charge near the sputter surface.

The performance of a charged particle beam blanker in a high resolution lithography system is determined primarily by spurious deflection during beam switching. To achieve an optimum blanker design, therefore, it is necessary to calculate spurious deflection as a function of the design parameters. The spurious deflection of a beam blanker which is composed of two pairs of blanking plates centred about a knife edge is evaluated using analytical methods. The results derived from these analytical methods explain all the important characteristics of such a beam blanker. Despite the rough approximations, the analytical results agree well with more accurate numerical calculations.

Beam switching Cassegrain antenna for millimeter wave radio astronomical measurements, describing RF and electronic systems

An electron gun and deflection system used to study transient beam‐plasma interactions is described. The gun produces a 1 or 2 mm diam beam which can be switched off or on in ∼0.5 nsec. Two such guns used in a two beam device can easily excite large amplitude plasma oscillations. Measurements of damping in the time domain were made by measuring the damping rate of these oscillations following beam cutoff.

The trochotron high-speed beam switching tube is described and the characteristics discussed. Expressions for the maximum discrimination and maximum continuous counting rates are derived. Binary, single pulse and sine wave drive circuits are discussed. Methods of extending the number of output channels and of generating staircase or analogue waveforms are illustrated. Details are given of remote digitron read-out, and mention made of a method of modulation.