Emil Nilsson

Ultra Low Power Wake-Up Radio Using Envelope Detector and Transmission Line Voltage Transformer

An ultra-low power wake-up radio receiver using no oscillators is described. The radio utilizes an envelope detector followed by a baseband amplifier and is fabricated in a 130-nm complementary metal-oxide-semiconductor process. The receiver is preceded by a passive radio-frequency voltage transformer, also providing 50 Ω antenna matching, fabricated as transmission lines on the FR4 chip carrier. A sensitivity of -47 dBm with 200 kb/s on-off keying modulation is measured at a current consumption of 2.3 μ A from a 1 V supply. No trimming is used. The receiver accepts a -13 dBm continuous wave blocking signal, or modulated blockers 6 dB below the sensitivity limit, with no loss of sensitivity.

Envelope detector sensitivity and blocking characteristics

This paper presents analytical expressions for the sensitivity of a low power envelope detector driven by a weak RF signal in the presence of a blocking signal. The envelope detector has been proposed for low power Wake-Up radios in applications such as RFID and wireless sensor systems. The theoretical results are verified with simulations of a modern short channel MOS transistor in a commonly used circuit topology. A discussion around a tutorial example of a radio frontend, consisting of an LNA and a detector, is presented. It is shown that the sensitivity of a low power envelope detector can reach −62 dBm with a low power LNA and in presence of a CW blocker.

Radar Interferometric Measurements With a Planar Patch Antenna Array

A planar patch antenna array has been made for radar interferometry. The antenna array consists of 32 rectangular patches on a ceramic loaded teflon substrate. The patches are individually coupled to the microwave electronics in two orthogonal circular polarizations. The radar interferometer is intended for topographic imaging in industrial environment, in this case, a blast furnace producing hot metal for the steel and metal industry. Ordinary imaging techniques with IR or visible radiation are not possible to use due to high temperatures, scattering from dust and particles. A model of blast furnace burden material surface was measured and detected.

Power Consumption of Integrated Low-Power Receivers

With the advent of Internet of Things (IoT) it has become clear that radio-frequency (RF) designers have to be aware of power constraints, e.g., in the design of simplistic ultra-low power receivers often used as wake-up radios (WuRs). The objective of this work, one of the first systematic studies of power bounds for RF-systems, is to provide an overview and intuitive feel for how power consumption and sensitivity relates for low-power receivers. This was done by setting up basic circuit schematics for different radio receiver architectures to find analytical expressions for their output signal-to-noise ratio including power consumption, bandwidth, sensitivity, and carrier frequency. The analytical expressions and optimizations of the circuits give us relations between dc-energy-per-bit and receiver sensitivity, which can be compared to recent published low-power receivers. The parameter set used in the analysis is meant to reflect typical values for an integrated 90 nm complementary metal-oxide-semiconductor fabrication processes, and typical small sized RF lumped components.

A low power-long range active RFID-system consisting of active RFID backscatter transponders

In this paper we present a novel active radio frequency identification system consisting of transponders with low complexity, low power consumption, and long system reading range. The transponders low complexity and small circuit integration area indicate that the production cost is comparable to the one of a passive tag. The hardware keystone is the transponders radio wake-up transceiver, which is a single oscillator with very low power consumption. The communication protocol, based on frequency signalling binary tree, contributes to the low complexity of the tag architecture. More than 1500 tags can be read per second. The average transponder ID read-out delay is 319 ms when there are 1000 transponders within reach of the interrogator. The calculated expected life time for a transponder is estimated to be almost three years.

A pharmaceutical anti-counterfeiting method using time controlled numeric tokens

An anti-counterfeit and authentication method using time controlled numeric tokens enabling a secure logistic chain is presented. Implementation of the method is illustrated with a pharmaceutical anti-counterfeit system. The method uses active RFID technology in combination with product seal. Authenticity is verified by comparing time controlled ID-codes, i.e. numeric tokens, stored in RFID tags and by identical numeric tokens stored in a secure database. The pharmaceutical products are protected from the supplier to the pharmacist, with the possibility to extend the authentication out to the end customer. The ability of the method is analyzed by discussion of several possible scenarios. It is shown that an accuracy of 99.9% telling the customer she has an authentic product is achieved by the use of 11-bit ID-code strings.

A new CMOS radio for low power RFID applications

A novel radio receiver circuit, functioning as a tuned active, detecting antenna, is described. The receiver is suggested to be part of a new radio system with the potential of competing with the range capability of active RFID-tags and, through its low power and long lifetime, with passive RFID-tags. The circuit is outlined and the functionality is verified by simulations and measurements. A 24 MHz discrete prototype showed better than −70 dBm sensitivity and 5 kHz bandwidth, with a power consumption of 102 μW. Simulations of a monolithic implementation were performed at 2.5 GHz. The detector is modeled by using 180 nm CMOS transistors. In simulations the power consumption for the detector is below 125 μW at a sensitivity of −83 dBm and a bandwidth of 9 MHz. Our conclusion is that this novel simple circuit architecture is well suited for monolithic implementation of a low power transceiver.

60GHz vital sign radar using 3D-printed lens

There is an increased interest in contact-less vital sign monitoring methods as they offer higher flexibility to the individual being observed. Recent industrial development enabled radar functionality to be packed in single-chip solutions, decreasing application complexity and speeding up designs. Within this paper, a vital sign radar has been developed utilizing a recently released 60GHz frequency modulated continuous wave single-chip radar in combination with 3D-printed quasi-optics. The electronics development has been focused on compactness and high system integration using a low cost design process. The final experiments prove that the radar is capable of tracking human respiration rate and heartbeat at the same time from a distance of 1m.