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This paper presents the design and development of four channel digital TR module for Ku band.The four channel TR module for Ku band consists of consists of digital part and RF part. DDS, TR control, AD, DDC and echo transmission constitute the digital transceiver part of the digital TR module. Two-stage frequency conversion and filtering, circulator, limiter, multi-stage LNA and multi-stage PA constitute the the RF transceiver part of the digital TR module. At present, the digital TR module has completed the program design, production and processing, testing.

Microwave photonic technologies, which upshift the carrier into the optical domain, have facilitated the generation and processing of ultra-wideband electronic signals at vastly reduced fractional bandwidths. For microwave photonic applications such as radars, optical communications and low-noise microwave generation, optical frequency combs are useful building blocks. By virtue of soliton microcombs, frequency combs can now be built using CMOS-compatible photonic integrated circuits. Yet, currently developed integrated soliton microcombs all operate with repetition rates significantly beyond those that conventional electronics can detect, preventing their use in microwave photonics. Access to this regime is challenging due to the required ultra-low waveguide loss and large dimensions of the nanophotonic resonators. Here, we demonstrate soliton microcombs operating in two widely employed microwave bands, the X-band (~10 GHz, for radar) and the K-band (~20 GHz, for 5G). Driven by a low-noise fibre laser, these devices produce more than 300 frequency lines within the 3 dB bandwidth, and generate microwave signals featuring phase noise levels comparable to modern electronic microwave oscillators. Our results establish integrated microcombs as viable low-noise microwave generators. Furthermore, the low soliton repetition rates are critical for future dense wavelength-division multiplexing channel generation schemes and could significantly reduce the system complexity of soliton-based integrated frequency synthesizers and atomic clocks.Nanophotonic microwave synthesizers in the X-band (10 GHz, for radar) and K-band (20 GHz, for 5G), based on integrated soliton microcombs driven by a low-noise fibre laser, link the fields of microwave photonics and integrated microcombs.

Over recent years, the surge in mobile communication has deepened global connectivity. With escalating demands for faster data rates, the push for higher carrier frequencies intensifies. The 7–20 GHz range, located between the 5G sub-6 GHz and the mm-wave spectra, provides an excellent trade-off between network capacity and coverage, and constitutes a yet-to-be-explored range for 5G and 6G applications. This work proposes a technological platform able to deliver CMOS-compatible, on-chip multi-frequency, low-loss, wide-band, and compact filters for cellular radios operating in this range by leveraging the micro-to-nano scaling of acoustic electromechanical resonators. The results showcase the first-ever demonstrated low insertion loss bank of 7 nanoacoustic passband filters in the X-band. Most of the filters showcase fractional bandwidths above 3% and sub-dB loss per stage in an extremely compact form factor, enabling the manufacturing of filters and duplexers for the next generation of mobile handsets operating in the X-band and beyond. This work addresses the fundamental challenge of the frequency up-scaling of microacoustic devices. The manuscript presents the first bank of on-chip multi-frequency, low-loss, wideband, and compact passband filters for mobile 5G and 6G applications.

In the context of plasma beam driven wakefield acceleration, we design and numerically test an ideal working point that exploits the resonant behavior of a train of driving bunches with ramped charge in order to accelerate a trailing bunch to high energy. The working point consists in a train of four bunches generated by an RF X-band photo-injector with the energy of 1.2 GeV. The bunch current profile is shaped by means of hybrid compression stage exploiting the combination of velocity bunching and magnetic chicane. The charges are properly calibrated in order to maximize the transformer ratio up to RT=8. The trailing bunch has a triangular shape and a peak current I=3 kA. By means of a 2.4m long plasma channel we simulated the acceleration of the trailing bunch up to 5 GeV mainly preserving the quality of the accelerated beam. The simulations were performed in cylindrical symmetry with the hybrid kinetic-fluid code Architect.

The mechanical and electronic properties of two-dimensional materials make them promising for use in flexible electronics 1 – 3 . Their atomic thickness and large-scale synthesis capability could enable the development of ‘smart skin’ 1 , 3 – 5 , which could transform ordinary objects into an intelligent distributed sensor network 6 . However, although many important components of such a distributed electronic system have already been demonstrated (for example, transistors, sensors and memory devices based on two-dimensional materials 1 , 2 , 4 , 7 ), an efficient, flexible and always-on energy-harvesting solution, which is indispensable for self-powered systems, is still missing. Electromagnetic radiation from Wi-Fi systems operating at 2.4 and 5.9 gigahertz 8 is becoming increasingly ubiquitous and would be ideal to harvest for powering future distributed electronics. However, the high frequencies used for Wi-Fi communications have remained elusive to radiofrequency harvesters (that is, rectennas) made of flexible semiconductors owing to their limited transport properties 9 – 12 . Here we demonstrate an atomically thin and flexible rectenna based on a MoS 2 semiconducting–metallic-phase heterojunction with a cutoff frequency of 10 gigahertz, which represents an improvement in speed of roughly one order of magnitude compared with current state-of-the-art flexible rectifiers 9 – 12 . This flexible MoS 2 -based rectifier operates up to the X-band 8 (8 to 12 gigahertz) and covers most of the unlicensed industrial, scientific and medical radio band, including the Wi-Fi channels. By integrating the ultrafast MoS 2 rectifier with a flexible Wi-Fi-band antenna, we fabricate a fully flexible and integrated rectenna that achieves wireless energy harvesting of electromagnetic radiation in the Wi-Fi band with zero external bias (battery-free). Moreover, our MoS 2 rectifier acts as a flexible mixer, realizing frequency conversion beyond 10 gigahertz. This work provides a universal energy-harvesting building block that can be integrated with various flexible electronic systems. Integration of an ultrafast flexible rectifier made from a two-dimensional material with a flexible antenna achieves wireless energy harvesting of Wi-Fi radiation, which could power future flexible electronic systems.

As electromagnetic absorbers with wide absorption bandwidth are highly pursued in the cutting-edge electronic and telecommunication industries, the traditional dielectric or magnetic bulky absorbers remain concerns of extending the effective absorption bandwidth. In this work, a dual-principle strategy has been proposed to make a better understanding of the impact of utilizing conductive absorption fillers coupled with implementing artificial structures design on the absorption performance. In the comparison based on the microscopic studies, the carbon nanotubes (CNTs)-based absorbers are confined to narrow operating bandwidth and relatively fixed response frequency range, which can not fulfill the ever-growing demands in the application. With subsequent macroscopic structure design based on the CNTs-based dielectric fillers, the artificial patterns show much more broadened absorption bandwidth, covering the majority of C-band, the whole X-band, and Ku-band, due to the tailored electromagnetic parameters and more reflections and scatterings. The results suggest that the combination of developing microscopic powder/bulky absorbers and macroscopic configuration design will fundamentally extend the effective operating bandwidth of microwave.

HighlightsThe eco-friendly shaddock peel-derived carbon aerogels were prepared by a freeze-drying method.Multiple functions such as thermal insulation, compression resistance and microwave absorption can be integrated into one material-carbon aerogel.Novel computer simulation technology strategy was selected to simulate significant radar cross-sectional reduction values under real far field condition..Eco-friendly electromagnetic wave absorbing materials with excellent thermal infrared stealth property, heat-insulating ability and compression resistance are highly attractive in practical applications. Meeting the aforesaid requirements simultaneously is a formidable challenge. Herein, ultra-light carbon aerogels were fabricated via fresh shaddock peel by facile freeze-drying method and calcination process, forming porous network architecture. With the heating platform temperature of 70 °C, the upper surface temperatures of the as-prepared carbon aerogel present a slow upward trend. The color of the sample surface in thermal infrared images is similar to that of the surroundings. With the maximum compressive stress of 2.435 kPa, the carbon aerogels can provide favorable endurance. The shaddock peel-based carbon aerogels possess the minimum reflection loss value (RLmin) of − 29.50 dB in X band. Meanwhile, the effective absorption bandwidth covers 5.80 GHz at a relatively thin thickness of only 1.7 mm. With the detection theta of 0°, the maximum radar cross-sectional (RCS) reduction values of 16.28 dB m2 can be achieved. Theoretical simulations of RCS have aroused extensive interest owing to their ingenious design and time-saving feature. This work paves the way for preparing multi-functional microwave absorbers derived from biomass raw materials under the guidance of RCS simulations.

Carbon nanotubes (CNTs) incorporated polymeric composites have been extensively investigated for microwave absorption at target frequencies to meet the requirement of radar cross-section reduction. In this work, a strategy of efficient utilization of CNT in producing CNT incorporated aramid papers is demonstrated. The layer-by-layer self-assembly technique is used to coat the surfaces of meta-aramid fibers and fibrils with CNT, providing novel raw materials available for the large-scale papermaking. The hierarchical construction of CNT networks resolves the dilemma of increasing CNT content and avoiding the agglomeration of CNT, which is a frequent challenge for CNT incorporated polymeric composites. The composite paper, which contains abundant heterogeneous interfaces and long-range conductive networks, is capable of reaching a high permittivity and dielectric loss tangent at a low CNT loading, and its complex permittivity is, so far, adjustable in the range of (1.20–j0.05) to (25.17–j18.89) at 10 GHz. Some papers with optimal matching thicknesses achieve a high-efficiency microwave absorption with a reflection loss lower than −10 dB in the entire X-band.

HighlightsThe microwave absorbing performance of alloy@C composites can be controlled through regulating ratio of metal ions.Carbon-based alloy@C composites exhibit the potential stability of microwave absorption with almost the whole Ku band for the practical application.Magnetic/dielectric@porous carbon composites, derived from metal–organic frameworks (MOFs) with adjustable composition ratio, have attracted wide attention due to their unique magnetoelectric properties. In addition, MOFs-derived porous carbon-based materials can meet the needs of lightweight feature. This paper reports a simple process for synthesizing stacked CoxNiy@C nanosheets derived from CoxNiy-MOFs nanosheets with multiple interfaces, which is good to the microwave response. The CoxNiy@C with controllable composition can be obtained by adjusting the ratio of Co2+ and Ni2+. It is supposed that the increased Co content is benefit to the dielectric and magnetic loss. Additionally, the bandwidth of CoNi@C nanosheets can take up almost the whole Ku band. Moreover, this composite has better environmental stability in air, which characteristic provides a sustainable potential for the practical application.

In the article a new design of a fiber-optic communication line for microwave transmission between devices in a radar station is considered. New designing solutions for the developed fiber-optic communication line are proposed. The results of experimental research are represented.