Abstract: An off-chip signal is provided to a differential branch-line directional coupler implemented entirely on-chip. The coupler produces differential quadrature signals, which are then buffered and applied to a quadrature mixer. The coupler is implemented entirely on-chip using microstrip transmission lines. The coupler is made up of a plurality of rings and a plurality of underpasses connecting ports of the rings, wherein each of the plurality of rings is made up of four branch lines, and each branch line having an electrical length of one-quarter wavelength at the center design frequency. Coupling between the plurality of branch lines of the rings may be varied.

Abstract: Improved phased array techniques and architectures are provided. For example, a linear phased array includes N discrete phase shifters and N?1 variable phase shifters, wherein the N?1 variable phase shifters are respectively coupled between adjacent output nodes of the N discrete phase shifters such that the N discrete phase shifters reduce an amount of continuous phase shift provided by the N?1 variable phase shifters. Each of the N discrete phase shifters may select between two or more discrete phase shifts. The N discrete phase shifters also preferably eliminate a need for a variable termination impedance in the linear phased array.

Abstract: Principles of the present invention provide improved amplifiers such as low-noise amplifiers. While such amplifiers may be suitable in many applications, such amplifiers may provide improved noise, gain and stability performance at millimeter-wave frequencies. In a first aspect of the invention, an amplifier includes a first amplifying stage including a common-base transistor, and a second amplifying stage, coupled to the first amplifying stage, including a cascode transistor pair. The amplifier may be implemented in accordance with a silicon-based technology (e.g., silicon germanium) and may employ microstrip shunt-stub transmission lines as matching networks.

Abstract: A bypass switch topology for a low-noise amplifier is provided. In one aspect of the invention, an amplifier includes at least one signal amplifying transistor, coupled between an input terminal and an output terminal associated with the amplifier, for amplifying a received input signal. The amplifier also includes a bypass switch, coupled to the at least one signal amplifying transistor, for providing a gain (e.g., high-gain) mode operation and a bypass mode operation, the bypass switch including two transistors. In the gain mode operation, the two transistors of the bypass switch are off and the at least one signal amplifying transistor amplifies the received input signal and passes the amplified signal to the output terminal. In the bypass mode operation, the two transistors of the bypass switch are on, the at least one signal amplifying transistor is turned off, and the received input signal is passed directly from the input terminal to the output terminal.