COUPLED NON-UNIFORM BI-SQUID: A NUMERICAL INVESTIGATION

This work investigates through numerical simulations a novel device that improves dynamic range and linearity. The standard DC SQUID can increase in linearity by adding a third junction, changing to a device known as the bi-SQUID. It is known that the dynamic range can increase by connecting SQUIDs in series, and it has been shown that non-uniformity in the loops sizes in arrays of SQUIDs can produce a unique 'anti'-peak at the zero magnetic flux (device know as a SQIF). Thus, combining these ideas we can improve the dynamic range and design a highly linear device with a unique 'anti'-peak. Hence, this device can be referred to as a bi-SQIF or non-uniform bi-SQUID array. Results have shown that the maximum voltage swing increase proportional to N, where N is the number of loops connected in series. The spur free dynamic range also improves as N increases, which is directly related to the linearity of the device. Therefore, we have designed a device which can lead to improvements which can be applicable to low noise amplifier (LNA), and provide a platform for creating "electrically" small antennas.