high linearity with the proper selection of parameters this is somewhat surprising since a josephson junction presents a nonlinear inductance however the junction nonlinearity is able to compensate the nonlinearity of the device in order to achieve an improved linearity close to 120 db for significant loop inductances which are necessary to achieve large coupling to external signals it is to be understood by those skilled in the art that any other nonlinear reactance that functions in a similar way would have a similar effect on reducing the nonlinearity of the system transfer function the linearity dependence of the shunt junction i c3 on critical current at different inductances of the squid loop is shown in fig5 the linearity is calculated using a single tone sinusoidal flux input of amplitude a a max 0 2 where a max corresponds to the flux amplitude u03c6 0 4 and measuring the total harmonic distortion in db this result shows that the linearity is sharply peaked for each value of l li c u03c6 0 but with different optimized values of i c3 very large values of linearity as high as u02dc 120 db are achievable fig6 shows how the linearity parameter varies as a function of the signal amplitude for other parameters fixed the linearity decreases as the signal approaches the maximum value a serial array of bi squids can be implemented to increase the dynamic range up to a value comparable with the response linearity moreover a serial sqif providing a single non periodic voltage response with a single triangular dip at zero magnetic flux can be implemented single bi squids serial arrays of bi squids and a prototype of an active electrically small antenna based on a bi squid array were designed fabricated and tested using a.