Recently, we have shown the emergence of oscillatory behaviour in unforced bistable systems having dynamics of the general form: tx equiv partU(x,t)/partx, subject to carefully crafted coupling schemes. Here, we present experimental results obtained on a physical system implemented with N=3 coupled ferromagnetic cores; the oscillatory behaviour is triggered when the coupling constant exceeds a threshold value, and, more importantly, the oscillation characteristics are sensitive to weak external dc magnetic fields. The oscillations afford then a novel detection scheme for fluxgate magnetometer. In this paper, we introduce another idea; using the coupled core fluxgate, in the detection of time-periodic fields of very low frequency. In this case measurements can be realized in a "power-saver" mode wherein the coupled setup can be, initially, subthreshold (i.e. non-oscillating) and be triggered into oscillation by the advent of the target (oscillatory) field. Preliminary experiments of this novel operation mode are here presented

Nonlinear antennas combine advances in nonlinear dynamics, active antenna design, and analog microelectronics to generate beam steering and beam forming across an array of nonlinear oscillators. Nonlinear antennas exploit two phenomena typically shunned in traditional designs: nonlinear unit cells and interelement coupling. The design stems from nonlinear coupled differential equation analysis that by virtue of the dynamic control is far less complex than the linear counterparts by eliminating the need for phase shifters and beam forming computers. These advantages arise from incorporating nonlinear dynamics rather than limiting the system to linear quasisteady state operation. A theoretical framework describing beam shaping and beam forming by exploiting the phase, amplitude, and coupling dynamics of nonlinear oscillator arrays is presented. Experimental demonstration of nonlinear beam steering is realized using analog microelectronics.