Generalised method of current excitation reconstruction from near-field data of planar, cylindrical and spherical antenna arrays

Currently chemotherapy, radiation and surgery are the widely accepted treatments for cancer. A fourth modality, hyperthermia, or heat treatment, is emerging as an adjuvant cancer treatment along with radiation or chemotherapy, and works as a booster, sometimes even doubling the effects of these standard treatments. Hyperthermia essentially heats the cancer region to around 42°C by precisely controlled electromagnetic radiation in the 27, 900 or 2400 MHz frequency range. The re-emergence of hyperthermia is primarily due to advanced antenna technology, which can precisely target the tumour volume, while delivering minimal energy to neighbouring healthy tissue. The precise focusing of the electromagnetic beam is realised either by focusing plates or lenses, or by conformal antenna arrays. In order to achieve efficient array near-field control for hyperthermia applications, electronic control of the array currents is essential to control the beam over the tumour volume and achieve uniform heating. This paper reports a generalised analytical technique to reconstruct the array currents from a specific near-zone electric field profile. This reconstruction technique is applicable to conformal arrays with planar, cylindrical or spherical geometry. Several simulations have been carried out to test the validity and accuracy of the reconstruction algorithm.