An attempt to generalize the current knowledge of passive magnetic field transducers— SQUID and induction sensors (ISs) (MAFCOPS)—and to incorporate elements of both designs in order to find a way to improve their performance data (PD) by cre- ating, in theory, a combined transducer— superconducting induc- tion magnetometer (SIM). State-of-the-art IS design is shown with two modifications for applications in outer space—LF with sensi- tivity threshold (ST) 5 pT  Hz to 5  fT /rootHz in frequency range (FR)20Hz-16kHzandHFwithST0 5pT     Hz   1fT     Hzin FR 10 kHz 10 MHz. The superconducting field-effect transistor (SuFET) is incorporated into a wide-band IS device in order to ac- quire an ST below 1 fT Hz in the FR from small values of Hertz to tens of megahertz (0 1-107 Hz). The proposed magnetometer circuit consists of both a room-temperature or cooled (up to super- conductive) pickup coil (PC) and a SuFET. Both the transfer function and the ST for SIM are analytically investigated proceeding from the equivalent and noise circuit, respectively. The sensitivity improvement of some SIM variants is shown in comparison with other state-of-the-art MAFCOPS.

Some contradiction between the possibility of deep cooling of the device and considerable equivalent area of the PC could be resolved by cooling only the amplifying circuit. As a result of requiring both BJT and FET on the input of the amplifying device, there is additional variance that could be resolved by em- ploying the SuFET device in reverse connection.