Massive use of wireless devices in the 2.4 GHz band is producing what has been called the “ISM Revolution”. ISM mean: Industrial, Scientific and Medical. ISM bands are frequency bands of free use (portions of the radio-electric spectrum, for which no license is required). It doesn´t mean that the devices operating on ISM bands are exempt from the regulations governing the use of those bands, both from the standpoint of radio (power, channel, duty cycle, etc.) and Electromagnetic Compatibility (emission and immunity).

Wireless technologies are being extended in exponential way, especially in the 2.4 GHz, which is nearly saturated with standards like Zigbee, Bluetooth and Wi-Fi. The presence of numerous devices in this band, including microwave ovens, makes the likelihood of interference is high and that the devices have to be designed with high frequency selectivity and very good quality at link level. This is also the reason because of new spread spectrum techniques (FHSS and DSSS) be needed to increase the immunity to electromagnetic noise.

WiTech Wireless Radio Module for Wireless Sensor NetworkAnother of the handicaps from the use of 2.4 GHz band is that it is coincident with the resonant frequency of water, and therefore tends to be absorbed more quickly by structural elements (walls, ceilings, etc..), which makes difficult a good and big cover.

Choose the Sub-1GHz band, largely help to solve the problems of the 2.4 GHz although we must also take into account the limitations on restrictions on the duty cycle, no interoperability with other systems, and geographical limitation such as different frequency operation bands, 868MHz can no operate in USA or 915MHz can no operate in Europe, for example.

PREMO & Wireless Technology designed “Witech” radio modules that operate at Sub-1GHz band of 868MHz and 915MHz. There are a variety of models available, from the front-end (external CPU) to the radio module integrated broadband or narrow band, with different CPU capabilities, and RF hardware interface: micro-strip antenna, ceramics, whip or SMA connector for external antenna, they can be adapted with total flexibility to design the final product.

Applications of WiTech Wireless Radio Modules

  • Automatic Meter Reading Networks (AMR) for water, electricity and gas
  • General Purpose Ad-Hoc Sensor Networks
  • Wireless Domotica Systems
  • Industrial Control
  • Solar Panel Monitoring Networks
  • Marinas Dock Pedestals
  • Real Time Location Systems (RTLS)
  • Indoor Navegation and Access Control
  • Healthcare and Wellness Networks
  • Weather Stations
  • Watering and Irrigation Control Networks

Source: PREMO Group