Figure 1
From: Wireless MRI Colonoscopy for Sensitive Imaging of Vascular Walls
The operation of wireless powered amplification. (a) The schematic diagram of a cylindrically symmetric Wireless Amplified NMR Detector (WAND) with a horizontal (lower frequency) resonance mode and a longitudinal (high frequency) resonance mode. (b) The picture of a 6.3-mm long detector made of a patterned layer of copper clad polyimide wrapped around a 2.4-mm diameter polyurethane cylinder. (c) The solid curve is the S 21 curve measured for the passive detector without pumping power, and the dotted curve is that measured for the active detector in the presence of pumping power at about 0.3 dB below the detector’s oscillation threshold. (d) A WAND device inserted inside the rat rectal with inductive coupling to the pumping loop and the external surface coil. (e) The arrangement for phantom test with the WAND inserted in the center of a water tube placed above the surface coil. The distance separation between the WAND and the external surface coil is about 22 mm.
