dBm Radio Frequency Research Articles

Dielectric‐Doped 2D Tellurium Diodes for Zero‐Bias Radio Frequency Power Detection

AbstractThis work presents a 2D tellurium (Te)‐based diode that exploits the doping achieved by atomic layer deposited (ALD) Al2O3 to enhance its rectifying performance. The proposed device comprises a Schottky junction that is dielectric‐doped to significantly reduce the reverse bias current. A boosted current responsivity four times higher compared to that of undoped devices is achieved, maximizing the performance for radio frequency (RF) power detectors. The application measurement results demonstrate sensitivities as low as −45 dBm, and at −30 dBm RF input power outstanding tangential responsivities up to 6.5 kV W–1, 4.3 kV W–1, and 650 V W–1 at 0.5, 1, and 2.5 GHz, respectively, while reaching linear dynamic range (DR) of over 30 dB. These are the highest reported values for 2D‐based material devices by almost two orders of magnitude. Furthermore, the DR is ≈10 dB larger compared to state‐of‐the‐art power detectors based on bulk semiconductors.

Self-Powered wireless sensor node based on RF energy harvesting and management combined design

Environmental energy-harvesting technologies, such as solar, vibration, and radio frequency (RF) energies, can effectively increase the lifespan of wireless sensor nodes while reducing their size, weight, and cost. Generally, RF energy harvester design methods are based on ideal energy sources and resistive loads, whereas real RF energy conversion and management are extremely complex and cannot be verified using conventional design methods. In this study, an RF energy harvesting and management combined design method is proposed to attain the requisite output parameters of an RF energy harvester to enable load operation during the design phase. Based on the proposed method, a highly integrated high-performance RF energy-harvesting wireless sensor node (RF-EH WSN) is constructed. The experimental results indicate that the input energies for both the simulation and measurements are equal and consistent (-10 dBm) for identical expected output voltages and energies. The proposed WSN can achieve self-powered operation at a distance of 13.5 m from a 27 dBm RF energy source.

Flexible and Wearable Hybrid RF and Solar Energy Harvesting System

In this article, we demonstrate a flexible and wearable hybrid radio frequency (RF) and solar energy harvesting system for powering wearable electronic devices. The system consists of a flexible transparent antenna, a flexible transparent rectifying circuit, and an amorphous silicon solar cell. By utilizing transparent stacked structure, the rectenna and the solar cell can provide more hybrid output power to accommodate more application scenarios. The flexible transparent antenna shows two impedance matching bandwidths of 3.5–3.578 and 4.79–5.09 GHz, covering n78/n79 fifth-generation (5G) communication frequency band and 5-GHz WiFi frequency band. At the frequency of 3.5 GHz, the flexible transparent rectifying circuit achieves a high RF-to-dc conversion efficiency of 54.67% at 13 dBm RF input power. In the room with a light intensity of 210 lux, compared with a single solar cell, the hybrid energy harvesting system can obtain an additional 35.6%–769.5% output power when the RF source power is varied from 4 to 10 dBm. These results demonstrate that the proposed flexible and wearable RF-solar energy harvester can provide reliable electric power supply, which can be a potential candidate for powering wearable electronic devices, distributed sensors and IOT devices.

Enhancing off-axis integrated cavity output spectroscopy (OA-ICOS) with radio frequency white noise for gas sensing.

Injecting radio frequency (RF) white noise to the current driving of the laser can broaden the laser emission linewidth and efficiently suppress cavity-mode noise in off-axis integrated cavity output spectroscopy (OA-ICOS). The effect of the injected RF noise level on the cavity-mode noise and the deformation of the absorption line shape in off-axis integrated cavity output spectroscopy (OA-ICOS) with a distributed feedback laser (DFB) at 1.65 µm were investigated. We measured methane at different concentrations between 0.1 ppmv and 2 ppmv associated with a -20 dBm RF noise injection. A linear spectral response of the intensity of the cavity output spectra with the CH4 concentration was observed. A threefold improvement in the detection limit was achieved compared to unperturbed OA-ICOS. The response time of the improved OA-ICOS system is about 30 s and the minimum detectable concentration (MDC) of CH4 is 7.6 ppbv, which corresponds to a minimum detectable fractional absorption scaled to the path length of 7.3 × 10-10 cm-1. The noise equivalent absorption sensitivity of the system is 5.51 × 10-9 cm-1Hz-1/2.

Dual-band aperture-coupled rectenna for radio frequency energy harvesting

The article presents a dual-band aperture-coupled rectenna for radio frequency (RF) energy harvesting at 2.45 and 5 GHz application. The rectenna consists of a dual-band π-shaped slot-etched aperture-coupled antenna, designed at the lower substrate of two FR4 substrate layers and a dual-band rectifier. The proposed antenna design also introduces the harmonic suppression of third- and higher order harmonics, ranging from 6 up to 10 GHz from the asymmetrical stubs design at the transmission feedline. The dual-band rectifier is designed to operate at 2.45 and 5 GHz frequency, successfully achieving high conversion efficiency at 68.83% and 49.90% with the optimum load resistor of value 700 Ω and 1.1 kΩ. The minimum DC voltage of 0.167 and 0.236 V with 0 dBm RF input power can be increased when greater RF power is being applied to it, increasing its flexibility to cater various low-power applications.

Phase-Modulated Analog Photonic Link With a High-Power High-Linearity Photodiode

We investigate phase-modulated analog photonic link performance using interferometric detection with a Mach–Zehnder interferometer (MZI) under different bias conditions and a high-power high-linearity modified unitraveling carrier (MUTC) photodiode (PD). Expressions for radio frequency (RF) small signal gain and the optimal MZI bias point for RF gain are derived, and noise figure (NF) and third-order spurious free dynamic range (SFDR3 ) are analyzed. Using a 28- μ m-diameter MUTC single PD with 23 dBm RF output power under 155-mA saturation current at 10 GHz, we measured a record-high link gain of 25 dB, 18 dB NF, and ${\text{114}}\;{\text{dB}} \cdot {\rm{H}}{{\rm{z}}^{{\text{2/3}}}}$ SFDR3 at 130 mA photocurrent with an optimally biased MZI. By using a 24- μ m-diameter balanced MUTC PD pair with 21 dBm RF output power at 108 mA at 10 GHz, we obtained a 16 dB link gain, 16 dB NF, and ${\text{118}}\;{\text{dB}} \cdot {\rm{H}}{{\rm{z}}^{{\text{2/3}}}}$ DR3 at 100 mA total dc photocurrent when the MZI was biased at quadrature. The RF gain at both MZI bias points is in good agreement with our calculations.

A 5 dB NF 100 KHz 1/F corner and 35 dBm OIP3 down conversion mixer using dynamic current injection and derivative superposition method

This letter presents the design and measurement of high OIP3, low flicker noise double-balanced Gilbert cell down conversion mixer in CMOS process. The key features of proposed mixer are dynamic current injection and derivative superposition. Since the flicker noise (1/f noise) have a strongly affect mixer's noise figure (NF), a dynamic current injection is used to reduce the flicker noise. The derivative superposition method has an auxiliary common gate stage of radio-frequency (RF) input stage to cancel each third order intermodulation distortion (IMD3) and can provide a high third order output intercept point (OIP3). The proposed down conversion mixer is fabricated in 0.18 μm CMOS technology. And this letter highlights the performances of the proposed mixer in terms of: flicker noise (i.e., noise figure: 5 dB at 100 kHz), third order output intercept point (i.e., OIP3, typically 35 dBm), and the conversion gain (i.e., typ. 17.3 dB) from −20 dBm RF input at 2.4 GHz. © 2016 Wiley Periodicals, Inc. Microwave Opt Technol Lett 58:1720–1723, 2016

Analysis of partially depleted absorber waveguide photodiodes

This paper presents the analysis and characterization of partially depleted absorber (PDA) photodiodes. Coupling to these photodiodes is achieved through a planar short multimode waveguide (PSMW) structure. Electric transport in the PDA structure has been investigated and an equivalent electric circuit was developed. Measurements on 5/spl times/20 /spl mu/m/sup 2/ PSMW PDA photodiodes have shown 0.80 A/W responsivity with a fiber mode diameter as high as 6 /spl mu/m. The transverse electric/transverse magnetic polarization dependence was <0.5/spl plusmn/0.3 dB with -1-dB input coupling tolerances as high as /spl plusmn/2.0 and /spl plusmn/1.3 /spl mu/m for horizontal and vertical directions. The -3-dB bandwidth was 50 GHz, and the -1-dB compression current at 40 GHz was 17 mA corresponding to +4.5 dBm radio frequency (RF) power. Compared to similar evanescently coupled p-i-n photodiodes, the saturation current has been significantly improved while maintaining comparable bandwidth and high responsivity.

A two-channel optical downconverter for phase detection

Experimental results for a two-channel optical downconverter link operating from 2 to 18 GHz are presented. Using low-noise preamplifiers results in a noise figure (NF) of 8.5-14 dB over the frequency range of 2-18 GHz. For the first time, relative phase measurements between optically downconverted signals have been performed. An in-phase/quadrature phase-measurement technique indicates a phase precision of /spl plusmn/2/spl deg/ with as little as -60 dBm radio frequency (RF) received power. Comparing the optical microwave downconverter to an electrical microwave downconverter in terms of phase detection reveals similar performance between the two systems.