Whitepapers

Budgeting Harmonics for ZigBee Front End Modules

This document details how to specify harmonics for a ZigBee FEM. It reviews the requirements from the different regulatory standards, analyzes through simulation harmonics content of offset quadrature phase-shift keying (OQPSK) spread spectrum modulation and evaluates the effects of the measurement bandwidth and detector on the harmonics level of both sine and ZigBee waveforms. Finally, measurement data is provided to illustrate the simulations results.
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Simulation of Multipath Fading Effects in Mobile Radio Systems

RF signals transmitted via wireless mobile channels suffer from several effects like smallscale fading and signal dispersion and distortion. This paper reviews these effects and simulates Rayleigh and Rician multipath fading channels with a comparison between them in terms of the effect of RF signal random fluctuations, average received signal level, outage probability, and effect of Doppler shift. In addition to that, signal dispersion occurring to pulses transmitted through these types of channels has also been discussed and simulated.
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Analysis and Design of the Rectangular Microstrip Patch Antennas for TM0n0 Operating Mode

The analysis of rectangular microstrip patch antenna (RMPA) operating on the TM0n0 modes is presented. The characteristic parameters such as dielectric substrate, ground plane aspect ratio, input impedance as a function of the feed point position and the frequency effects have been theoretically investigated for these modes. The Finite Element Method and MATLAB model have been used for optimize and design RMPA operating at TM010 mode. The antenna has been carry out on the FR4 substrate and the characteristics has been measured with Vector Network Analyzer.
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Tag Designs and Techniques Used in HF RFID Item Level Tracking

The choice and placement of a RFID tag on a product requires an investigation to determine optimal performance. The current technology of HF tags is focused on the mass production of low cost paper thin tags that have maximized read range performance perpendicular to the broad plane of the tag. Incorporating both these tag designs for use within the RFID architecture allows for flexibility of product placement and orientation while maintaining optimum performance.
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Problem of Physical Non-realizable Equivalent Current Amplitude Distributions in Waveguide Antenna Feeding Slots

In this paper the Full-Wave design method of the non-resonant waveguide multislots antenna is presented. The internal mutual couplings between adjacent radiating slots are considered in the described method. The problem of the physical nonrealizability of some equivalent currents amplitude distributions feeding slots, caused by the internal mutual couplings between slots is also presented. Some corrective solutions which allow solving mentioned problem are proposed. In order to confirm the usefulness of the presented solutions the obtained results are compared to their equivalents reached in computer simulations with the use of CST Microwave Studio.
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New 110 dB, 10 MHz to 8 GHz, Electronic Step Attenuator for Fast-Switching Microwave Signal Generators

A step attenuator finds wide-spread usage as a means of accurately extending the attenuation range of test and measurement instruments. A typical application would be to extend the output amplitude range of a microwave signal generator. Often an amplitude control loop can accurately set the power or gain level over three or four decades of range, but frequently this is not enough range. Historically, the mechanical step attenuator has been the preferred solution.


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High-accuracy Noise Figure Measurements Using the PNA-X Series Network Analyzer

Noise figure is an important figure-of-merit that describes the amount of excess noise present in a component or system. Minimizing noise figure reduces system impairments that result from noise, such as degraded voice quality of cell-phone calls, or decreased detection range of radar systems. Measurement accuracy is very important, in both R&D and manufacturing environments. In R&D, better noise figure accuracy means that there will be a better correlation between simulations and measurements, helping designers refine circuit models faster. In manufacturing, improved accuracy provides better correlation among multiple test stations, minimizing rework and increasing test throughput. Higher accuracy also allows better device specifications, yielding more competitive products.
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The Advantages of Multi-rate Harmonic Balance (MRHB)

Harmonic balance (HB) analysis is a method used to calculate the nonlinear, steady-state frequency response of electrical circuits. It is extremely well-suited for designs in which transient simulation methods prove acceptable, such as dispersive transmission lines in which circuit time constants are large compared to the period of the simulation frequency, as well as for circuits that have a large number of reactive components. In particular, harmonic balance analysis works extremely well for microwave circuits that are excited with sinusoidal signals, such as mixers and power amplifiers.


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Silicon BiCMOS: The Optimal Technology for RF Power

The debate over GaAs versus CMOS has been reinvigorated by recent industry events. This includes the sale of CMOS cellular power amplifier (PA) house Axiom Microdevices to GaAs cellular PA manufacturer Skyworks as well as the emergence from “stealth mode” of CMOS cellular PA startups Black Sand Technologies and Javelin Semiconductor. In terms of market share, since TRW Semiconductor paired with RF Micro Devices in the mid-­‐ to-­‐late 1990s, the GaAs heterojunction bipolar transistor (HBT) has been the standard bearer for mobile phone PA performance, cost, and manufacturability. GaAs houses that design, manufacture and package their own PAs and other RF components dominate today’s cellular power amplifier market.


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