The “Loopole” Antenna: A Hybrid Coil Combining Loop and Electric Dipole Properties for Ultra-High-Field MRI

Figure 10

Reflection (S₁₁) measurements demonstrate a 30 MHz shift in the resonant frequency of a dipole when its distance to the phantom varied from 25 mm to 5 mm. The frequency response of the loopole was much more stable in this regard with a 3 MHz frequency shift.

(a)

(b)