Search

This letter presents a novel monolithic integrated frequency multiplier circuit for free space power generation in the ${W}$ -band (75–110 GHz). The circuit is based on a submicrometer GaAs Schottky diode monolithically integrated with a slot antenna on a GaAs semi-insulating substrate. The fabricated diode with an air-bridged Schottky contact and a U-shaped ohmic contact showed an ideality factor of about 1.25 and a zero bias cutoff frequency higher than 1.25 THz. Using input signals between 15 and 50 GHz, the free space power generated in the ${W}$ -band corresponding to $\times 2$ , $\times 3$ , $\times 4$ , and $\times 5$ frequency multiplication was measured and showed minimum isotropic conversion losses (with antenna) of 11.5, 16.9, 23.7, and 26.4 dB, respectively. [ABSTRACT FROM AUTHOR]

The paper presents the experiments regarding a Schottky diode fabricated on a graphene monolayer using asymmetric metallic contacts. The current is in the mA range, which is with orders of magnitude higher than for reported Schottky diodes prepared on graphene bilayers or related graphene materials. Moreover, this device exhibits a DC controllable phase shift of more than 20 degrees in the range 40-65 GHz. [ABSTRACT FROM AUTHOR]

The paper presents the experimental and modeling results of a microwave slot antenna in a coplanar configuration based on graphene. The antennas are fabricated on a 4 in. high-resistivity Si wafer, with a ~300 nm SiO2 layer grown through thermal oxidation. A CVD grown graphene layer is transferred on the SiO2. The paper shows that the reflection parameter of the antenna can be tuned by a DC voltage. 2D radiation patterns at various frequencies in the X band (8-12 GHz) are then presented using as antenna backside a microwave absorbent and a metalized surface. Although the radiation efficiency is lower than a metallic antenna, the graphene antenna is a wideband antenna while the metal antennas with the same geometry and working at the same frequencies are narrowband. [ABSTRACT FROM AUTHOR]

The radio-frequency identification (RFID) concept is expended to millimeter-wave frequencies and millimeter-wave identification (MMID) in this paper. The MMID concept and a comparison with UHF RFID are presented, showing the limitations and benefits of MMID. Three feasible applications are suggested for MMID, which are: 1) wireless mass memory; 2) an automatic identification system with pointing functionality; and 3) transponder communication with automotive radar. To demonstrate the feasibility of the MMID system, experimental results for both downlink and backscattering-based uplink are presented at 60 GHz. [ABSTRACT FROM AUTHOR]

This letter describes the manufacture and characterization of surface acoustic wave (SAW) devices on GaN/Si devoted to applications above the 5-GHz frequency range. The SAW structures consist of two face-to-face interdigitated transducers (IDTs), placed at different distances. Using a TiAu metallization, 80-nm-thick and advanced e-beam lithographical techniques with IDTs with fingers and spacings 200 nm wide have been obtained on the GaN layer. On wafer measurement of the S parameters have demonstrated the operation at approximately 5.6 GHz. The frequency response of the devices is explained in detail. [ABSTRACT FROM AUTHOR]

This letter describes the fabrication and the morphological and microwave characterization of film bulk acoustic resonator structures, supported on very thin GaN membranes. We have demonstrated, by employing both white-light profilometry as well as X-ray diffraction, the low deflection and low stress of the GaN membranes supporting the resonator metallization. Using as test structure two FBAR structures connected in series, by a floating backside metallization, we have obtained resonance frequencies of 6.3 GHz for a 0.5-μm-thick membrane. The quality factor, at 6.3 GHz, was higher than 1100. [ABSTRACT FROM AUTHOR]

These days, electronics are moving toward faster, smaller, more effi cient, yet cost effective, solutions. In doing so, the limits of what materials are currently available within the technologies are frequently reached. Because of this, the hunt for new materials that are endowed with disruptive, enhanced properties and a high degree of compatibility with standard processes, has become paramount. In this diffi cult quest, graphene has shown proven results as an emblematic protagonist, seeming to answer many needs. Characterized by superior electric and mechanical performance, it is also quite compatible with conventional manufacturing techniques. Hence graphene may become a key enabling material, paving the way for a new generation of high-speed nanoscale electronics with consequences and breakthroughs similar to that of silicon's in the last few decades. This article will try to encompass the evolution of this fascinating material, beginning with early observations and moving into the practical microwave applications that are envisioned for its bright future. [ABSTRACT FROM PUBLISHER]