High-resolution millimeter-wave imaging (HR-MMWI), with its high discrimination contrast and sufficient penetration depth, can potentially provide affordable tissue diagnostic information noninvasively. In this study, we evaluate the application of a real-time system of HR-MMWI for in-vivo skin cancer diagnosis. 136 benign and malignant skin lesions from 71 patients, including melanoma, basal cell carcinoma, squamous cell carcinoma, actinic keratosis, melanocytic nevi, angiokeratoma, dermatofibroma, solar lentigo, and seborrheic keratosis were measured. Lesions were classified using a 3-D principal component analysis followed by five classifiers including linear discriminant analysis (LDA), K-nearest neighbor (KNN) with different K-values, linear and Gaussian support vector machine (LSVM and GSVM) with different margin factors, and multilayer perception (MLP). Our results suggested that the best classification was achieved by using five PCA components followed by MLP with 97% sensitivity and 98% specificity. Our findings establish that real-time millimeter-wave imaging can be used to distinguish malignant tissues from benign skin lesions with high diagnostic accuracy comparable with clinical examination and other methods.

This paper reports on a novel super-wideband micro-hemispherical antenna with application in millimeter-wave medical imaging. The antenna is composed of a hemispherical shell suspended above a substrate and can be fabricated using a fabrication technology originally developed for micron-scale electromechanical resonators. The antenna exhibits a wide fractional bandwidth of more than 80% (from 64 GHz to 150 GHz) and a high gain of 8.6 dBi at its center frequency. Radiation parameters of the antenna are characterized and the effect of its super-wideband behavior on pulsed millimeter-wave imaging is demonstrated. Finally, a preliminary array configuration composed of two antennas placed side-by-side in the vicinity of a skin-mimicking target is evaluated and the ability to fully detect the target has been demonstrated.

This study presents a theoretical design study of a novel three-dimensional micromachined hemispherical shell antenna for ultra-wideband millimetre-wave imaging applications. The antenna is composed of a hemispherical metallic shell which is suspended on top of a high-resistivity silicon substrate using a thin silicon stem. The antenna exhibits two different operational modes and an exceptionally wide bandwidth of more than 80 GHz at the centre frequency of 120 GHz. Simulation results indicate that the antenna performance is highly sensitive to geometrical variations and hence to fabrication inaccuracies. Performing a complete sensitivity analysis using full-wave simulations requires numerous simulation steps and is therefore time-intensive and impractical. This study provides closed-form solutions for all performance metrics of the antenna, followed by a comprehensive theoretical-based sensitivity analysis for evaluating the effects of fabrication imperfections on its bandwidth. The antenna structure is then calibrated for ultra-wideband operations and low sensitivities to fabrication inaccuracies.

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