Please consider this device

MRF24J40MC is a 2.4 GHz IEEE 802.15.4 radio transceiver module intended for longer range applications.  The MRF24J40MC has an external antenna connector, matching circuitry, and supports the ZigBee®, MiWi™, MiWi P2P and MiWi Pro protocols.  The MRF24J40MC module connects to hundreds of PIC® microcontrollers via a 4-wire SPI interface and is an ideal solution for AMR/AMI metering, wireless sensor networks, home automation, building automation and consumer applications.

  2.4 GHz IEEE 802.15.4 Transceiver Module

  Supports ZigBee®, MiWi™, and MiWi P2P protocols

  FCC (USA), IC (Canada), ETSI (Europe)

  External Antenna Connector : Ultra Miniature Coaxial (U.FL)

  Simple four-wire SPI interface to PIC® microcontroller

  Integrated PA/LNA- Tx power +20 dBm to +23dBm (depending on the antenna)Rx sensitivity -108 dBm (antenna gain not included)

  Hardware CSMA-CA Mechanism, Automatic ACK response

  Hardware security engine (AES-128)

  Automatic packet retransmit capable

  Small size: 0.9" x 1.3" (22.9 mm x 33.0 mm), Surface Mountable