University of Pretoria

Tinus Stander

Nishant Singh

Piotr Jan Osuch

The invention relates to a tunable, silicon-based negative-resistance circuit () and to an active filter () for E-band frequencies (60 to 90 GHz). A base of a transistor () is connected to an on-chip inductive transmission line () which has a length of approximately a quarter-wavelength at a frequency of 83.5 GHz. The transmission line connects a DC voltage source () to the base terminal of the transistor () in order to bias the base. Another DC voltage source () is connected to the collector of the transistor () to bias the transistor. A capacitor () operatively bypasses or decouples the voltage source () in order to shunt high frequencies or alternating current (AC) signals to ground. The emitter terminal of the transistor () is connected to ground through a resistor () to limit the collector current (l). The circuit gives rise to improved quality factor of resonators.

Negative-resistance circuit and active filter for millimetre wave frequencies

A second-order all-pass network has at least three Second Generation Current Conveyors (CCIIs). A network input is connected or connectable to a Y port of a first CCII, a Z port of the first CCII is connected to a Y port of a second CCII, an X port of the first CCII is connected to a Y port of a third CCII, and a network output is connected or connectable, directly or indirectly, to a Z port of the second CCII. The X port of the first CCII is connected via a first network element to ground, the Z port of the first CCII is connected via a second network element to ground, an X port of the third CCII is connected via a third network element to ground, and an X port of the second CCII is connected via a fourth network element to ground.

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Pretoria, South Africa

Tinus Stander