Precision Tumor Detection in Breast Cancer through Cutting-Edge Millimeter-Wave Antennas

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in the brain and breast.Breast cancer, which can also affect men, is among the most common cancers in women and results from the uncontrolled growth of cells in breast tissue.Research indicates that approximately one in eight women will develop breast cancer in their lifetime, making it a leading cause of cancer-related deaths worldwide, accounting for 6.6% of all cancer deaths [1][2].
Breast examination employs several imaging techniques, including X-ray mammography, ultrasound, MRI, and positron emission tomography (PET).Additionally, microwave imaging is a diagnostic method with unique benefits.For instance, X-ray mammography can be uncomfortable due to ionizing radiation and may occasionally yield inaccurate results.PET scans tend to have lower resolution, while MRI is known for its high cost.On the other hand, radio frequency detection is a safe and cost-effective alternative that can function independently of a physician's direct involvement.Microwave imaging is especially advantageous because it is less expensive and does not involve ionizing radiation [3].
Microwave Imaging (MWI) is an innovative medical diagnostic tool that has received significant attention for its use in detecting breast tumors, brain tumors, early-stage heart failure, and for health monitoring.In MWI, microwaves are sent through the human body with a transmitting antenna that also serves as a receiver.This antenna gathers data by differentiating between microwave signals scattered by various tissues within the body.The collected radiated and scattered energy is then processed for precise diagnosis and analysis.This research proposes a mmWave antenna sensor that shows great promise for diagnosing earlystage tumors and detecting very small malignant masses.Initial experiments indicate that operating frequencies above 30 GHz can detect tumors as small as 1 mm in breast phantoms.Additionally, this antenna system, operating in this high-frequency range, can enhance gain and efficiency, making it suitable for 5G and future high-speed communication systems [4].For 5G communication infrastructure, there is a growing need for smaller, faster, and higher bandwidth antenna technologies.Single-element microstrip mmWave antennas are particularly promising candidates [5] [6].The proposed system operates at a central frequency of 33 GHz, with a wide bandwidth of 2.10 GHz aimed at improving the resolution of mmWave images.An important advantage of this antenna sensor is its capability to detect very small tumor cells (≥1 mm, i.e., microstrip patch antennas to achieve high resolution, focusing on emerging tumor detection designs.The study involved four patch antennas operating at 33 GHz, positioned at the sides of a container.The methodology centered on tracking changes in S-parameters to assess tumor tissue formation and determine its location.Subsequent sections detail the characterization of breast tissue models, followed by the antenna design process.Simulation scenarios, results, and evaluations are presented before the conclusion.

II. DESIGN OF BREAST MODEL
Breast cancer begins with irregular growth within the complex tissue of the breast, encompassing fat, fibrous tissue, glandular tissue, skin, and the areola.This cancerous growth often starts by invading the breast glands or ducts.When there is an abnormal proliferation of fibrous and glandular tissue or a decrease in fatty tissue, it can lead to the formation of dense breast tissue, which serves as an early sign of cancer development [7].
The dielectric properties of breast tissue vary significantly depending on the presence or absence of tumors, which has been extensively studied from 1980 to the present [8][9].These properties are characterized by permittivity and tangent loss, with different tissues exhibiting distinct values at various frequencies.Table 1 presents the material properties of a breast tissue model derived from previous literature [10].In the design of the 3D breast model, considerations include skin, fibrous tissue (fibro), fat, and glandular tissue.Figure 1 illustrates a basic representation of the 3D breast tissue model, and its dimensions are detailed in Table 2.

III. DESIGN OF PATCH ANTENNA
Patch antennas are compact and efficient communication devices widely utilized in radio frequency (RF) and microwave applications.This study focuses on the rectangular patch antenna structure, chosen for its affordability and compactness, ideal for potential integration into microwave imaging systems.The initial design of a millimeter-wave antenna involves several key steps [11][12].Initially, a resonant frequency of 33 GHz was selected, with RT/duroid 5880LZ chosen as the dielectric material for the substrate.The necessary dimensions were calculated using specific equations ( 1), (2), and (3), and these details are provided in Table 3. Subsequently, the dimensions were simulated using the HFSS electromagnetic (EM) simulator.
An iterative parametric study was then conducted to achieve the desired performance outcomes.

IV. SIMULATION SCENARIOS
The simulation considers three different scenarios: a breast without a tumor, a breast with a tumor, and tumors located in various positions, as depicted in Figure 3.This approach allows for comprehensive testing of the antenna's performance under different conditions, providing insights into its ability to detect and localize tumors effectively.

V. RESULTS AND DISCUSSIONS
The designed single millimeter-wave antennas (SMWA) and the breast tissue model were simulated using a commercially available HFSS electromagnetic simulator.A crucial parameter for assessing antenna performance is the return loss, which is characterized by the scattering parameter S11.The S11 characteristics of the SMWA were computed and are presented in Figure 5.At the operating frequency of 33 GHz, the SMWA demonstrated a return loss of -19.33 dB, indicating a strong signal reflection and efficient performance.Furthermore, the antenna achieved a bandwidth of 2.10 GHz, where the return loss remains below -10 dB.This wide bandwidth is essential for high-resolution imaging applications.The design also ensures proper impedance matching, which enhances the radiation efficiency and overall effectiveness of the antenna system.The radiation pattern is a crucial aspect of antenna performance, particularly in medical imaging applications where precision and clarity are paramount.In Figure 7, the radiation pattern of the single millimeter-wave antenna (SMWA) demonstrates waves extending to the far field, showcasing broadside radiation characteristics.This type of radiation pattern is especially beneficial for medical imaging as it provides uniform coverage and consistent signal strength across the imaging area.Broadside radiation ensures that the electromagnetic waves are directed perpendicularly to the surface of the antenna, allowing for deeper penetration into biological tissues.This is vital for accurately capturing high-resolution images of internal structures, such as detecting tumors in breast tissue or abnormalities in other organs.The uniformity and directionality of the broadside radiation pattern enhance the clarity and detail of the medical images, making the SMWA an effective tool for diagnostic imaging.By minimizing signal loss and maximizing the depth of penetration, this antenna design supports the precise detection and localization of medical conditions, thereby improving diagnostic accuracy and patient outcomes.The coverage area and link budget of a single millimeter-wave antenna (SMWA) are significantly influenced by its Total Peak Gain (TPG) [11].In medical imaging applications, a high TPG is crucial as it directly impacts the quality and resolution of the captured images.These scenarios are depicted in Figure 9.The simulations considered these three distinct conditions to evaluate the antenna's performance.The ideal resonant frequency of the antenna, initially set at 33 GHz, significantly shifted to 34.5 GHz upon detecting a 1 mm tumor cell within the breast phantom.Figure 9 illustrates how the resonant frequency varies when the tumor is positioned differently within the breast tissue.This shift in frequency indicates the antenna's sensitivity to the presence and location of the tumor, demonstrating its potential effectiveness for early-stage tumor detection.The ability to detect such small tumors and observe changes in resonant frequency highlights the SMWA's suitability for precise and accurate breast cancer diagnostics.Table 4 illustrates how the frequency varies as the tumor's position changes within the breast phantom model.This data provides insights into how the antenna's resonant frequency shifts in response to different tumor locations, offering valuable information for optimizing the antenna's performance in detecting and localizing tumors within breast tissue.Understanding these frequency variations is crucial for enhancing the antenna's sensitivity and accuracy in medical imaging applications, particularly in early-stage breast cancer detection.

Figure 2 .
The top view illustrates the patch element positioned above the RT/duroid 5880LZ substrate, highlighting its configuration and placement.The ground view depicts the ground plane, which is essential for the antenna's operation and performance.This design ensures optimal transmission and reception of millimeter-wave signals, crucial for applications in high-frequency communication and imaging systems.

Figure- 3 :
Figure-3: Simulation scenarios; (a) breast without tumor, (b) breast with tumor and (c) tumor in different position.The configuration of four single millimeter-wave antennas (SMWA) arranged at 90 degrees around the breast tissue model is illustrated in Figure 4.In the first scenario, breast tissue without any tumors was positioned at the center of the four antennas, and the simulation was carried out.In the second scenario, the setup remained the same, but a tumor with a 1 mm radius was introduced into the breast tissue.In the final scenario, the breast tissue containing the tumor was rotated by 45 degrees, and the simulation was performed to evaluate the impact of the positional change on the detection capabilities.

Figure- 4 :
Figure-4: Arrangement of Four Antennas with breast tissue model

Figure- 6 :
Figure-6: VSWR of SMWA Figure 8 illustrates a TPG of 7.07 dB, indicating the antenna's efficiency in directing energy towards the target area.A TPG of 7.07 dB ensures that the SMWA can effectively transmit and receive signals with minimal loss, which is essential for penetrating biological tissues and obtaining clear medical images.In practical terms, this high gain enhances the antenna's ability to detect fine details within the body, such as small tumors or other abnormalities.The improved signal strength and clarity afforded by a high TPG result in more accurate diagnostic imaging, enabling healthcare professionals to identify and treat conditions at an earlier stage.This is particularly beneficial in breast cancer screening, where early detection can significantly improve treatment outcomes.The robust performance of the SMWA, as indicated by its TPG, underscores its potential as a valuable tool in advanced medical imaging technologies.

Figure- 10 :
Figure-10: Different Situation Return Loss Characteristics of SMA

Table 1
Electrical material property of breast tissue.
The single millimeter-wave antenna (SMWA) structures were designed and connected via a 50Ω microstrip line, as shown in

Table 4
Shifted Resonant Frequencies with Tumor Position