Resistively Loaded Dielectric Biconical Antenna for Deep Tissue Pulse Delivery
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Solution Overview
Problem
Current electrical tissue treatment methods using sub-microsecond pulses face challenges in achieving deep, high-power indirect penetration without invasive electrodes, as power delivery falls off quickly with depth and existing antenna designs like prolate spheroid impulse radiating antennas are impractical due to large size and reflection losses at the air-tissue interface.
Innovation Solution
The development of resistively loaded dielectric biconical antenna systems that use a resistor ring to reduce electrical reflection and deliver sub-microsecond pulses effectively to depths of 0.1-5 cm, focusing energy through a dielectric cone and cylindrical waveguide with conductive plates, allowing for non-invasive treatment of biological tissues.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of moving object
If prolate spheroid impulse radiating antennas are used to focus deeply-situated targets, then deep penetration capability is improved, but antenna size becomes large and reflection loss at air-tissue interface increases making implementation impractical
Solution Approach 1:
The antenna is divided into multiple sections: a proximal wave-launching section with a dielectric cone and conductive plates, a cylindrical waveguide section, and a distal wave-emitting section. This segmentation allows each section to be optimized independently for its specific function while maintaining overall compact dimensions.
Solution Approach 2:
The patent employs a dielectric cone with specific permittivity values (e.g., εr = 2.56 or 4.0) to transform the electromagnetic wave characteristics. By changing the dielectric parameter, the antenna achieves better impedance matching and reduced reflection loss at the air-tissue interface while maintaining deep penetration capability.
2Power
If high power is applied to achieve deep penetration, then power delivery to depth is improved, but power actually delivered to tissue falls off quickly within a few millimeters
Solution Approach 1:
A cylindrical waveguide with specific dimensions (e.g., diameter 0.5-2 cm, length 1-5 cm) serves as an intermediary structure that guides and focuses electromagnetic energy. The waveguide maintains field intensity over distance, preventing rapid power fall-off and enabling effective energy delivery to deeper tissue regions.
Solution Approach 2:
The distal wave-emitting section is specifically designed with optimized geometry and material properties to concentrate electromagnetic energy at the target depth. This local optimization ensures that power is delivered precisely where needed rather than being dissipated uniformly throughout the tissue.
3Ease of operation
If sub-microsecond pulses are used for noninvasive stimulation, then noninvasive treatment is achieved, but it has proven exceptionally difficult to achieve deep, high-power indirect penetration of tissue
Solution Approach 1:
The antenna combines multiple materials with complementary properties: dielectric materials (such as Teflon or polyethylene) for wave launching, conductive materials for plates and waveguide, and resistive materials for the resistor ring. This composite structure enables both noninvasive operation and deep high-power penetration by optimizing each material's contribution to the overall system performance.
Solution Approach 2:
A resistor ring is introduced as an intermediary element to match impedance between the antenna and tissue, reducing reflections and improving power transfer efficiency. This allows sub-microsecond pulses to penetrate deeply into tissue while maintaining noninvasive external application.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
These antenna systems enable efficient delivery of sub-microsecond pulses to depths of 1-2 cm, achieving biological effects and local heating, with the resistor ring improving energy absorption and penetration, reducing discomfort and energy loss, and allowing for focused energy delivery.
Implementation Method 1
a proximal wave-launching section comprising a cone of dielectric material and one or more pairs of conducive plates extending over a portion of the cone of dielectric material; a waveguide extending distally from a base of the cone of dielectric material
Implementation Method 2
a resistor ring electrically connecting the one or more pairs of conductive plates and extending laterally at least partially around the distal wave-emitting section
Implementation Method 3
The heat may be generated by applying pulses at a high repetition rate, as demonstrated by examples of nanosecond pulsed experiments
Data Source
AI summary
Resistively loaded dielectric biconical antenna apparatuses, including systems and devices, that may be used to transmit very short electrical pulses (e.g., nanosecond, sub-nanosecond, picosecond, etc.) into tissue non-invasively at energy levels sufficient to invoke biological changes in the tissue. These resistively loaded dielectric biconical antenna apparatuses may include a resistor ring reducing internal reflection and reducing energy loss, as well as delivering longer pulses (e.g. microsecond to millisecond) to tissue.