Figure 5.

Maximum area rectangle fitted at the center (ΔB / $B_1^0$ = 0 and B₁ / $B_1^0$ = 1) of a fidelity profile (Figure 4b). All points inside the rectangle have a fidelity greater than 99% (called the 99fidelity rectangle). The dimension of this 99fidelity rectangle is (±0.57) × (±0.18), meaning the given composite pulse has 99% fidelity for the range of relative resonance offsets from −0.57 to +0.57 and relative RF amplitudes from −0.18 to +0.18.