Microwave medical imaging at Ka-band

We introduce a novel Ka-band microwave imaging system operating at 35 GHz. Central to the performance of this system is a direct field inversion algorithm requiring only one minute of processing time per image slice cross section. The imaging system is a single-frequency transmission device, consisting of a stationary single Ka-band transmit horn antenna and a Ka-band open-ended waveguide receive probe equipped with a position-scanning mechanism. Once these single-slice, single-frequency test data are captured, a 3D image of tissue structure is obtained through our Field Mapping Algorithm (FMA), which uses the two tangential electric field components on the exterior surface, be it a plane, a sphere, or a cylinder, to determine the field throughout the tissue interior. The tissue medium associated with the interior field distribution is thus revealed as to its structure by way of the field polarization attributes. Two test measurement results are presented, one for a biological, and one for an inanimate dielectric object. Good imaging is clearly evident in these two measurement cases, despite the significant and unavoidable microwave absorption in the millimeter range.