Modules presently under development use an electrostatically variable capacitive RF MEMS switch with a Q of 250 at 1 GHz. Typically five switches are used to provide 32 capacitance values to give a 10:1 tuning ratio Power consumption of the adaptive tuner is presently of the order of 4.4 milliwatts reducing 1 milliwatt in the future, insertion loss is about 0.5 dB, harmonics H2 H3 are <91 dBc and intermods IM3 are <117 dBm. A typical device will need to handle 3 billion cold switching cycles for GSM. 32 There is no present standards work ongoing on this but this would seem to be a useful future work item. Making Telecoms Work Table 5.7 PA options Option 1 Separate power amplifiers and individually band optimised TX/RX paths Option 2 Three separate modules, one for core bands from Band V 850 MHz up to 2.1 GHz, a second for 2.3 and 2.6 GHz, and a third for US and European DDR at 700/800 MHz Option 3 As option 2 but with the core band module extended down to 700 MHz Option 4 As option 3 but with the core band module extended up to 2.6 GHz Option 5 Three separate modules, one for sub-one-GHz, one for existing bands between 1 GHz and 2.1 GHz, one for 2.3/2.6 GHz Option 6 One broadband PA for all frequencies Every 1 dB of mismatch loss equates to 1 dB less output power and 1 dB loss of sensitivity. For a WCDMA phone at 1900/2100 MHz, a 1-dB loss will increase current drain by 70 mA. In low band GSM a 1-dB loss will increase current drain by 250 mA due to its higher average power (two watts rather than one watt). 5.6.8 RF PA and Front-End Switch Paths There are a range of views from RF PA component vendors as to how a multiband phone supporting 700, 800 and 2600 MHz will be implemented: The options are shown in Table 5.7. Option 1 - a single RF PA and band optimised matching network for each band. Option 2 - one PA module for Band V (US LTE 850 or E850), Band VIII (LTE 900), Band III (LTE1800), Band II (US LTE1900) and Band I (UMTS/LTE1.9/2.1). A second module would cover Band 40 (China LTE TDD at 2.3 GHz), Band VII (UM