Abstract: A mobile communication device has a number of selectable states, an antenna, and a communication circuit for transmitting and receiving communication signals. The mobile device also includes an impedance matching circuit having impedance matching networks. Each impedance matching network is associated with at least one of the selectable states of the mobile communication device and is configured to optimize the impedance match between the communication circuit and the antenna based on the selectable state of the mobile communication device with which the impedance matching network is associated. A switching network is included for coupling the antenna to the communication circuit together using one of the impedance matching networks based on a selected state of the mobile communication device.

Abstract: Circuits for continuously varying the gain control for a low noise amplifier (LNA) of a wireless receiver are described. The gain, input third order intercept point (IIP3) and noise figure (NF) of an LNA are continuously varied according to the received power levels, causing the receiver to utilize less current at different power levels. At high gain levels the IIP3and NF are at a minimum, while at low gain levels the IIP3and the NF are at a maximum. By continuously varying the gain of an LNA throughout the operational range, the present invention achieves wider dynamic range and higher power efficiency. According to one aspect, the present invention includes a power coupler and a power detector which are utilized to produce a rectified voltage which is proportional to the input power or output power of an LNA. The rectified voltage is utilized by a control circuit which produces a signal which controls the gain, IIP3and NF of the LNA.