Abstract: A wideband tunable frequency single-subband converter is proposed. The wideband frequency tunable converter operates within a wideband and tunable frequency range, and has process, voltage, and temperature (PVT) tracking capability. In one embodiment, the wideband converter comprises a frequency tunable polyphase filter having a plurality of switchable polyphase resistors. The polyphase resistors are controlled by a frequency tuning control signal to achieve wideband frequency tunability. In a preferred embodiment, a triode mode transistor is used as a polyphase resistor, and a different resistance value of the polyphase filter is realized by turning on one or multiple of the different transistors in triode mode. In addition, a constant Gm(R) bias generator is used to provide the gate biases to the triode mode transistors to maintain a constant and stable resistance value across PVT and other variation.

Abstract: A novel bi-directional vector modulator to be used as an active phase shifter is proposed. The advantages of the active phase shifter include: 1) Compact size—By active current combining technique, short transmission lines are used to perform signal combining rather than using area-consuming Wilkinson combiner or splitter; 2) High phase resolution and flexibility—phase interpolation can be performed by vector addition through m-path vector modulators; 3) High efficiency—no signal switch loss, only switched matching capacitor; 4) Simplified signal interconnection; 5) No passive combiner needed—eliminate large size and losses in the passive combiner); 6) Can have unequal combining and/or splitting by changing the gain of vector modulator, which is difficult to realize with passive combining and/or splitting network; and 7) Can combine different signals.

Abstract: A wideband tunable frequency single-subband converter is proposed. The wideband frequency tunable converter operates within a wideband and tunable frequency range, and has process, voltage, and temperature (PVT) tracking capability. In one embodiment, the wideband converter comprises a frequency tunable polyphase filter having a plurality of switchable polyphase resistors. The polyphase resistors are controlled by a frequency tuning control signal to achieve wideband frequency tunability. In a preferred embodiment, a triode mode transistor is used as a polyphase resistor, and a different resistance value of the polyphase filter is realized by turning on one or multiple of the different transistors in triode mode. In addition, a constant Gm(R) bias generator is used to provide the gate biases to the triode mode transistors to maintain a constant and stable resistance value across PVT and other variation.

Abstract: A bi-directional active combiner and splitter using bi-directional variable gain amplifiers (BD_VGAs) is proposed. Advantages of the proposed bi-directional active combiner and splitter includes the following 1) compact size—for each BD_VGA, cascode transistor pair is small and the same matching network is used by the cascode transistor pair for both directions; 2) high efficiency—no switching loss in signal path, only switched matching; 3) reduced passive trace loss and power consumption—simplified signal interconnection; 4) active current combining—eliminates large size in the passive combiner; 5) high input-output isolation—cascode and neutralization; 6) precise gain control and unequal combining or splitting—changing the gain of the BD_VGA; and 7) phase-invariant amplifier design.

Abstract: A novel bi-directional vector modulator to be used as an active phase shifter is proposed. The advantages of the active phase shifter include: 1) Compact size—By active current combining technique, short transmission lines are used to perform signal combining rather than using area-consuming Wilkinson combiner or splitter; 2) High phase resolution and flexibility—phase interpolation can be performed by vector addition through m-path vector modulators; 3) High efficiency—no signal switch loss, only switched matching capacitor; 4) Simplified signal interconnection; 5) No passive combiner needed—eliminate large size and losses in the passive combiner); 6) Can have unequal combining and/or splitting by changing the gain of vector modulator, which is difficult to realize with passive combining and/or splitting network; and 7) Can combine different signals.

Abstract: A bi-directional active combiner and splitter using bi-directional variable gain amplifiers (BD_VGAs) is proposed. Advantages of the proposed bi-directional active combiner and splitter includes the following 1) compact size—for each BD_VGA, cascode transistor pair is small and the same matching network is used by the cascode transistor pair for both directions; 2) high efficiency—no switching loss in signal path, only switched matching; 3) reduced passive trace loss and power consumption—simplified signal interconnection; 4) active current combining—eliminates large size in the passive combiner; 5) high input-output isolation—cascode and neutralization; 6) precise gain control and unequal combining or splitting—changing the gain of the BD_VGA; and 7) phase-invariant amplifier design.