I would like to design a ZigBee device, using Freescale's ZigBee compliant platform MC13213 with external dual antenna. Figure 14C (document number MC1321x. Rev. 1.2 05/2007, page 24) shows a preferable dual antenna configuration, but it has no nominal values. Would you suggest me document to read or give formulas, to calculate nominal values of capacitors and inductors to connect RX and TX antennas?