A phased array applicator based on open ridged‐waveguide antenna for microwave hyperthermia

Abstract

Radiative hyperthermia is a clinically applied cancer treatment modality where antenna design is crucial to achieving therapeutic goals. Serving as the building block of a phased‐array configuration, antennas are typically arranged in a cylindrical or elliptical array called applicator. This short communication proposes an elliptical phased array applicator based on a compact, UWB design from the category of double‐ridged horn antennas customized for hyperthermia systems. The performance of the antenna, named open ridged‐waveguide, has been experimentally assessed based on the quality metrics of the hyperthermic community. The proposed design achieves an ultra‐wideband range of operation from 400 to 800 MHz with an aperture size of 3 by 4 cm. Moreover, thanks to the shielding provided by the metallic housing, the design proves good isolation better than −30 dB throughout the band. The power deposition capability of the proposed applicator followed by the thermal analysis is also investigated for a realistic head and neck patient model. The results indicate very good quality metrics achieved in the treatment planning of the patient.

Micro-Opening Ridged Waveguide Tumor Hyperthermia Antenna Combined with Microwave-Sensitive MOF Material for Tumor Microwave Hyperthermia Therapy

“…Simple waveguide antennas exhibit a poor near-field focusing effect. To improve the radiation performance of the antenna, double ridges are added to the waveguide, so that the electromagnetic field is concentrated between the two ridges. , To ensure impedance matching, the outer conductor of the coaxial line is connected to the edge of the ridged waveguide, and the inner conductor is extended to the opposite ridge to achieve matching, forming a monopole radiator. In this experiment, an open double-ridged ladder-fed small waveguide antenna with a working frequency of 915 MHz was designed, as shown in Figure a–e.…”

An ultra‐wideband compact design for hyperthermia: Open ridged‐waveguide antenna

“…The capability of the antenna to deposit EM energy into a large, deep‐seated, intracranial tumour is exemplified in Figure 18. A hybrid PSO‐based beamforming technique [45] was used to find the coefficients of the antennas at 400 MHz for a simultaneous excitation. Figure 18a, 18b and 18c show the achieved power loss density distributions in the transverse, coronal, and sagittal planes, respectively.…”

“…Finally, the antennas were excited by discrete ports at 400 MHz. The excitation amplitudes and phases were calculated using an in‐house developed beamformer based on PSO, details of which are given elsewhere [45]. These parameters, optimised for the cost function of the hotspot‐tumour‐quotient (HTQ) [46], are then used to steer the focal point on the tumour and also to reduce the hotspots outside the targeted area.…”

Development of a metamaterial‐based compact applicator for hyperthermia

“…Noninvasive applicators are applied outside the body without any interstitial procedure. Further, it is classified into two groups, a single microwave applicator 4,5 and a radiofrequency (RF) phased array of antennas 5,6 . The drawbacks of microwave applicators are their fixed aperture size, bulkiness, high cost, and penetration depth (PD) only up to 20–30 mm from the skin surface.…”

“…array antennas due to their adjustment of amplitude and phase of antennas. 6,7 To mitigate these hindrances by using a single antenna that can enhance the PD and focus the field in the tissue. For this use, numerous antenna types have already been suggested in the literature.…”