In ultra-high-field magnetic resonance imaging (MRI), inhomogeneity of the radiofrequency transmit field (|B ₁ ⁺|) occurs due to wavelength shortening that results from interactions between the coil and the high dielectric subject. Even if a multiple transmit/receive (Tx/Rx) coil array is employed using the first-order clockwise circularly polarised (|CP₁ ⁺|) mode, |B ₁ ⁺| inhomogeneity is an insurmountable obstacle. A scheme utilising the CP₁ ⁺ mode for the odd-numbered coil elements and the third-order clockwise CP mode for the even-numbered coil elements in the multiple-element Tx/Rx coil array was investigated with the objective of increasing the |B ₁ ⁺| homogeneity at 300 MHz. The results of an electromagnetic simulation and a 7 T MRI experiment are presented and to illustrate the improvements achieved using the optimum CP mode combination is discussed.