Budgeting Harmonics For ZigBee Front-End Modules

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•Application Note: Budgeting Harmonics For ZigBee Front-End Modules

By Skyworks Solutions, Inc.

Introduction

The growth of low-power, cost-effective wireless radio systems is driving more applications to use the ZigBee® communication standard. Some of these applications require a signal to propagate over a short range. When installed in a large building or operating outdoors over a wide area, such a system may benefit from transmitting more power. A ZigBee radio system powered by a +20 dBm Power Amplifier (PA) significantly increases its range by 400 percent from 133 to 543 meters compared to a low power 0 dBm PA (Wloczysiak [1]).

However, a transmit PA may generate higher spurious emissions, particularly harmonic spurs. Additional filtering would be required to satisfy the radiated emission requirements of the different regulatory standards listed in Table 1.

This Application Note details how to specify harmonics for a ZigBee Front-End Module (FEM). Requirements from the different regulatory standards are reviewed and analyzed using the simulation harmonic content of Offset Quadrature Phase-Shift Keying (OQPSK) spread spectrum modulation. The effects of the measurement bandwidth and detector on the harmonics level of both sine and ZigBee waveforms are also evaluated. Finally, this document provides measurement data that illustrates the simulation results.

Click Here To Download:
•Application Note: Budgeting Harmonics For ZigBee Front-End Modules