A Technique for the Early Detection of Brain Cancer Using Circularly Polarized Reconfigurable Antenna Array

Abstract

In this paper, a technique for the early detection of brain cancer was proposed. The technique depends upon the use of an antenna and a model for the human head. The reflection coefficient (S11) was found for two cases: with and without tumor in the head model. The large increase of S11 due to the presence of the tumor provides a good indication for tumor detection. It also gives an idea about the size of the tumor. The antenna used was a reconfigurable four-element linear array of squared microstrip patches. Two arrays were designed one circularly polarized, the other linearly polarized. The antenna operates at Industrial Scientific and Medical (ISM) frequency 2.4 GHz. It was designed on FR-4 (lossy) substrate of relative permittivity 4.3 and thickness of 1.6 mm. To feed the array, a corporate feeding network was designed. The reconfigurability of the array was achieved using three single pole double throw (SPDT) switches. Two models of the human head were used; a specific anthropomorphic mannequin (SAM) model, and a 3-D head model consisting of four different head layers: skin, fat, skull and brain. The simulation calculates the reflection coefficient (S11) with and without tumor for circularly polarized (CP) and linearly polarized (LP) linear array. Calculations were taken for four sizes of the array. The best results were obtained with the four-element circularly polarized array. An increase in S11 of 1188% was obtained. Tumors as small as 5 millimeters (four-layer model) and 2.5 mm (SAM model) can be detected. Specific absorption rate (SAR) was calculated and found to be within the safe limit. A circularly polarized four-element linear antenna array was fabricated. The measured S11 and radiation pattern are in excellent agreement with simulated ones.

Keywords

• Antenna arrays
• brain cancer tumors
• circular polarization
• reconfigurable antenna
• S₁₁