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A new class of nondiffracting pulses based on focusing leaky waves
In this work, we propose an azimuthally-invariant periodic leaky-wave (LW) radiator for the generation of Bessel beams and X-waves by means of backward cylindrical LWs at millimeter wavelengths. A rigorous framework is first outlined to understand the theoretical constraints of such a novel design. A specific attention is devoted to the impact of the attenuation constant on the focusing properties
Liquid-crystal-based amplitude tuner and tunable SIW filter fabricated in LTCC technology
Tunable microwave devices will play an important role in future wireless systems, in which high-frequency bands, e.g. millimeter waves, will become promising, due to its huge spectrum availability. At such frequency bands, liquid crystals (LCs) exhibit low microwave loss, which is excellent compared with the other tuning elements. In this paper, LC-based microwave components are fabricated by usin
Transfer of AlGaN/GaN RF-devices onto diamond substrates via van der Waals bonding
We present a novel bonding process for gallium nitride-based electronic devices on diamond heat spreaders. In the proposed technology, GaN devices are transferred from silicon (Si) onto single (SCD) and polycrystalline diamond (PCD) substrates by van der Waals bonding. Load-pull measurements on Si and SCD heat spreaders at 3 GHz and 50 V drain bias show comparable power-added-efficiency and output
GaN-based single-chip frontend for next-generation X-band AESA systems
A next generation of active electronically scanned array (AESA) antennas will be challenged with the need for lower size, weight, power, and cost. This leads to enhanced demands especially with regard to the integration density of the radio frequency-part inside a / module. The semiconductor material GaN has proven its capacity for high-power amplifiers (HPA), robust receive components as well as
Micromachining integration platform for sub-terahertz and terahertz systems
We demonstrate a sub-terahertz (THz) and THz integration platform based on micromachined waveguides on silicon. The demonstrated components in the frequency range 225?325 GHz include waveguides, filters, waveguide vias, and low-loss transitions between the waveguide and the monolithic integrated circuits. The developed process relies on microelectromechanical systems manufacturing methods and sili
Convolutional neural networks for parking space detection in downfire urban radar
We present a method for detecting parking spaces in radar images based on convolutional neural networks (CNN). A multiple-input multiple-output radar is used to render a slant-range image of the parking scenario and a background estimation technique is applied to reduce the impact of dynamic interference from the surroundings by separating the static background from moving objects in the scene. A
Tunable -enhanced LC dual-band filtering at microwave frequencies in 0.13 µm SiGe BiCMOS
This paper presents an active -enhanced LC dual-band band-pass filtering approach using parallel synthesis techniques at X- and Ku-bands in 0.13 m SiGe BiCMOS technology. By employing two independently tunable parallel LC-tanks with either in-phase and out-of-phase addition, independently tunable dual-band filtering is achieved. For higher out-of-band (OOB) attenuation, subtraction of the two 2-or
K/Ka-band dual-polarized SIW-fed lens antennas for Rx/Tx integration
This contribution deals with array elements for K/Ka-band satellite communication terminals. It proposes an end-fire design realized in substrate integrated waveguide technology and featuring dual-band functionality, and dual circular polarization. The latter is achieved by means of a dual-band orthomode transducer. An extended hemispherical dielectric lens ensures good matching and radiation prop
Design and demonstration of acoustically optimized, fully-printed, BST MIM varactors for high power matching circuits
This work addresses the piezoelectric induced reduction of quality factor in fully-printed metal-insulator-metal (MIM) barium strontium titanate (BST) thick film varactors designed for high power operation. An acoustically optimized varactor design is presented and compared to a non-optimized high-power varactor. The design is utilized to present a narrowband acoustic suppression technique based o
Low-current cathode spatial harmonic magnetrons: analysis and realization based on metamaterial loaded slow wave structures
This paper provides an overview of theory, design, simulation, and fabrication of novel spatial harmonic magnetrons (SHMs). An approximate analysis which provides the guidelines for the design and predicts the important characteristics of these devices will be presented. This analysis shows that the metamaterial loaded SHMs can start generating power with very small cathode current densities which