Abstract: Systems and methods are disclosed to control the temperature of an RF hyperthermia system with minimum overshoot and to improve safety by, among other things, detecting a defective temperature sensor. Temperature overshoot may be minimized by compensating for the short-term temperature difference between the area being treated and the applicator delivering the RF energy. The RF energy may heat the tissue and then the tissue may transfer heat to the applicator sensor. The system may also adapt to various applicator sizes and shapes by modifying control loop coefficients based on initial probe response.

Abstract: A hyperthermia treatment system for heating a selected region within a target body that includes a power source and a plurality of electromagnetic applicators that are in electrical communication with the power source and arranged in a surrounding array around a focal region to concentrate their combined radiation output onto the focal region. The treatment system also includes a support mechanism that is adapted to support a target body within the surrounding array of applicators, and a positioning mechanism adapted to move the support mechanism and align the selected region within the target body with the focal region. Furthermore, the positioning mechanism is adapted to compensate for movement of the focal region in response to an interaction between the combined radiation output and the target body.

Abstract: A thermal therapy of body tissue with electromagnetic energy is controlled by feedback from one or more temperature sensors placed in the vicinity of the tissue to be treated. The temperature sensors are calibrated by comparing stabilized temperature values of the one or more temperature sensors against a normal range of body temperature and adjusting sensed temperature to a value within a normal body temperature range if the actual temperature value of a stabilized temperature sensor is less than the normal body temperature range. The temperature adjustment to the temperature sensor is maintained throughout the thermal therapy which reduces the risk of thermal damage to healthy tissue located near the tissue to be treated.

Abstract: The adipose areas of the body are simultaneously subjected to lipolysis, through the action of an apparatus that generates low-frequency electromagnetic waves, to extraction, out of the adipose cells, of the fatty acids released by the lipolysis, and to drainage of the fatty acids to the vascular and lymphatic system, through the action of a pressotherapy apparatus.

Abstract: This invention relates to novel hygienic-therapeutic or personal care devices that are based upon intense far-infrared sources in which radiation is generated by novel conductive materials. The conductive materials are specially designed and made to radiate ten to thousands times more intense far-infrared radiation than typical conductive materials, and such strong far-infrared radiation is achieved with high, typically greater than 90%, conversion efficiency of energy to radiation. The radiation properties of the proposed conductive materials do not follow the Wien's law (“black body” law). The devices are intended to be used in therapy, medicine, cosmetic technology, hygiene technology, or household use.

Abstract: A system 30 and method(s) 100 for thermal treatment of a selected target within a subject is disclosed. System 30 includes RF source 10, phase shifter 14, impedance matching network 11 and resonator 13. Stationary water molecules 1, such as those in fat cells, are heated. The invention is useful in selective heating of cellulite bodies as a means of treating cellulite.

Abstract: The present invention teaches an apparatus and method for physical therapy using prompt changing temperature from hot to cold. Its application in proper conditions may promote human body's self recovery function, restore balance for soft tissues and relieve inner pressure.

Abstract: A therapeutic microwave system comprises a support unit having two or more separable segments; a microwave power assembly positioned between two separated segments of the support unit and including two or more microwave power supply devices; position adjustment componentry; and a central processing unit. The system may further include a temperature sensor for monitoring a treated subject's exhaled air temperature in real time and adjusting microwave irradiation accordingly, and a cooling device for controlling the patient's brain temperature during treatment.

Abstract: A therapeutic chamber controls the targeted application of infrared radiation according to programs tailored to conditions or areas of the body in need of treatment. Programs are provided and may also be determined or designed by a treatment administrator or subject. An embodiment utilizes groups of carbon fiber impregnated infrared generating sheets to provide targeted radiation in an energy efficient fashion.

Abstract: A radio-frequency thermal balloon catheter includes a catheter tube including an outer tube and an inner tube, a balloon connected to an end part of the outer tube and an end part of the inner tube, and capable of coming into contact with a target diseased part when inflated, a radio-frequency electrode placed in the wall of the balloon or inside the balloon to transmit radio-frequency current, a lead wire electrically connected to the radio-frequency electrode, a temperature sensor capable of measuring temperature inside the balloon, and a swirling current producing means for making a fluid contained in the balloon swirl in a vertical plane in the balloon so as to reduce an upper-lower temperature difference between an upper part and a lower part of the interior of the balloon due to convection of the fluid to naught.

Abstract: A thermotherapy device (1) includes a basic housing (2) with walls (14) with a support for a patient and an especially transparent covering hood (3) for the basic housing (2), which covering hood can be moved between a closed position and an open position, so that the basic housing (2) is closed by the covering hood (3) in the closed position. A guide mechanism (4) is provided for mechanically guiding the motion of the covering hood (3) between the closed position and open position. A heater such as a convection heater with a blower heats the air and/or an air humidifier humidifies the air. The covering hood (3) is moved in a simple manner and access to the support for a patient is essentially not hindered by the covering hood (3) in the open position.

Abstract: An energy irradiation device for medical use to irradiate a living body with energy includes a data storage for storing data indicative of correlations between information about bloodstream quantities and amounts of tissue necrosed in living bodies for a plurality of living bodies differing in bloodstream quantity that are irradiated with a predetermined quantity of the energy, a calculation unit for calculating a quantity of the energy with which to irradiate a predetermined living body based on the data stored in the data storage, the information about the bloodstream quantity in the predetermined living body, and the amount of tissue to be necrosed in the predetermined living body.

Abstract: Methods are provided herein for affecting a region of a subject's body, comprising exposing the region to a cooling element under conditions effective to cool subcutaneous adipose tissue in said region; and increasing the blood flow rate to the cooled tissue by exposing the tissue to an energy source. Methods are also provided for treating subcutaneous adipose tissue in a region of a subject's body, comprising exposing said region to a cooling element under conditions effective to cool said tissue; and exposing the tissue to an energy source to increase the blood flow rate to the cooled tissue, thereby stimulating reperfusion in, and/or causing an ischemia-reperfusion injury to, the cooled tissue.

Abstract: A radiant therapeutic heating apparatus may include a radiant heat generating layer having a plane surface including an infrared radiator adapted to radiate heat evenly from its surface, a pair of flexible electrically insulating and radiation-permeable layers located adjacent and covering opposite sides of the layer, a thermal insulation layer disposed against and covering one of the electrically insulating layers, and a sealed radiation permeable envelope enclosing the heating apparatus. The flexible heat generating layer may include a fiberglass material impregnated with a resistive material, which material may provide a surface temperature, when current is conducted therethrough, of no greater than about 54 degrees Celsius. Current limiting thermostats may be provided to prevent energy and temperature spikes. A stiffening element may help protect the components, and may orient portions of a user's body (such as, e.g., but not limited to, the wrist for repetitive strain injuries) in a therapeutic position.

Abstract: An apparatus and method for performing warming therapy is described. In one exemplary embodiment, the apparatus includes a warming platform, a heating source, a controller, and a plurality sensors. The heating source comprises a plurality of heating elements forming a matrix, wherein each heating element is operable to heat a corresponding region of the warming platform. The controller is operatively coupled to the heating source for controlling the temperature in each region of the warming platform. The plurality of sensors are operatively coupled to the controller for sensing a physiological parameter of a patient (e.g., body temperature) residing on the warming platform, and providing one or more control signals to the controller for selectively controlling the heating elements.

Abstract: A low profile, mobile system for therapeutic application of heat such as far infrared (“FIR”) heat to an affected area of an individual's body including straps and a pad, the pad including a plurality of FIR emitting discs and heaters. The FIR emitting discs are ceramic discs of cordierite made of a mixture of magnesium oxide, aluminum oxide, silicon oxide and/or trace elements. The heat application system is designed for simple operation via a single button.

Abstract: A method of treating a patient is described herein. The method can include the steps of identifying a target that contains biological tissue and directing one or more pulses of electromagnetic radiation at the target. The pulses of electromagnetic radiation can cause a temperature increase per unit of time in the biological tissue. Additionally, the temperature increase per unit of time can cause the change in the cell function in the biological tissue and can be within a range of approximately one degree Celsius per second to approximately one degree Celsius per microsecond.

Abstract: A system 30 and method(s) 100 for thermal treatment of a selected target within a subject is disclosed. System 30 includes RF source 10, phase shifter 14, impedance matching network 11 and resonator 13. Stationary water molecules 1, such as those in fat cells, are heated. The invention is useful in selective heating of cellulite bodies as a means of treating cellulite.

Abstract: A new non-invasive approach is proposed that contemplates a method and apparatus to utilize two- or three-dimensional treatment patterns with a reverse thermal gradient to non-invasively heat a subjacent soft tissue structure through an intact tissue surface or an intact surface epithelium for clinical applications. For most clinical applications, an electromagnetic energy source with surface cooling is employed to heat the treatment patterns. Without limitation, the clinical applications include but are not limited to the treatment of post partum vaginal laxity, female incontinence, cervical incompetence with preterm labor, gastro-esophageal reflux, reduction of gastric reservoir capacity (for weight management), sleep apnea, snoring, pain management and the treatment of orthopedic injuries such as joint laxity and tennis elbow.

Abstract: A method of inducing local cell death in patient tissue is provided. The method includes generating first and second radiation, conveying the radiation to a focusing element, and focusing the radiation on a target with the focusing element. A system for inducing local cell death in patient tissue is also provided. The system includes a power source for generating narrow-band and/or ultra-wideband radiation, and a focusing element for focusing the radiation on a target.

Abstract: An application for a heat and light emitting pad has an array of light and heat emitting devices such as LEDS mounted on a circuit board and held within a sponge material. A controller provides a controlled amount of power to the LEDS such that the LEDS emit a therapeutic amount of heat and light for the treatment of pain. The heat and light emitting pad is a thin sheet for insertion between a person and a surface on which that person rests.

Abstract: A RF electrode for use in a device for thermal fat destruction and skin tightening is provided. The RF electrode comprises a handle, a cannula shaft that extends from the handle and in turn comprises a dielectric material. The shaft is insertable inside a body at a treatment area. The shaft also comprises an electrode tip that is positioned on the cannula at a location distal to the handle. The electrode tip comprises a RF conductive material. A device for thermal fat destruction and skin tightening and method therefore are also provided.

Abstract: To automatically control a treatment during which subcutaneous or intracutaneous irradiation by means of electromagnetic treatment radiation and possibly targeted electromagnetic radiation is carried out, the following steps are implemented: acquisition of several successive images l(t) of the treated zone by means of an external sensor (1), which is sensitive to the wavelength or the range of wavelengths of the electromagnetic treatment radiation or of the targeted electromagnetic radiation, the time interval (?) between two successive images [l(t?1); l(t)] being known, detection and localisation in each image l(t) of a light spot p(t) corresponding to the irradiation spot (S) of the electromagnetic treatment radiation or the targeted electromagnetic radiation, calculation for each light spot p(t) of at least one of the following parameters: the energy [eij(t) or Eij(t)] supplied from the power P(t) of the electromagnetic treatment radiation and the time interval (?) between two successive images [l(t?1); l(

Abstract: A hyperthermia treatment system for heating a selected region within a target body that includes a power source and a plurality of electromagnetic applicators that are in electrical communication with the power source and arranged in a surrounding array around a focal region to concentrate their combined radiation output onto the focal region. The treatment system also includes a support mechanism that is adapted to support a target body within the surrounding array of applicators, and a positioning mechanism adapted to move the support mechanism and align the selected region within the target body with the focal region. Furthermore, the positioning mechanism is adapted to compensate for movement of the focal region in response to an interaction between the combined radiation output and the target body.

Abstract: The present disclosure relates to thermal profiling systems for hypothermic and/or ablative energy systems and methods of their use. According to an aspect of the present disclosure, a system for profiling a thermal or electromagnetic treatment system, including an energy delivery probe, is provided. The profiling system includes a bath including a fitting supported on a side wall thereof configured for selective insertion of a distal tip of probe therethrough; a test gel disposed within the bath; and at least one piece of a reactive medium submerged in the test gel.

Abstract: Methods and systems for delivering electromagnetic energy to a patient's tissue with an attendant reduction in the pain experienced by the patient due to tissue heating. Electromagnetic energy is delivered from an electrode through a skin surface to heat a first region of tissue beneath the skin surface and a second region of the tissue between the first region and the skin surface. During the delivery of the electromagnetic energy, a temperature of the second region of the tissue is caused to oscillate between at least one maximum temperature and at least one minimum temperature. The temperature oscillation may be induced by a timed sequence of cryogen pulses delivered to the electrode, which in turn extracts thermal energy out of the second region of tissue through the contacting skin surface.

Abstract: Systems and methods for revitalizing aging skin using electromagnetic energy that is delivered using a plurality of needles that are capable of penetrating the skin to desired depths. A particular aspect is the capability to spare zones of tissue from thermal exposure. This sparing of tissue allows new tissue to be regenerated while the heat treatment can shrink the collagen and tighten the underlying structures. Additionally, the system is capable of delivering therapeutically beneficial substances either through the penetrating needles or through channels that have been created by the penetration of the needles.

Abstract: A system and method for interactive interstitial photo-dynamic tumour therapy and/or photothermal tumour therapy of a human or animal, said system comprising at least one radiation distributor, which is arranged for distribution of optical radiation from at least one radiation source to a reaction site, or from the reaction site to at least one radiation sensor. The radiation distributor comprises at least one translatory displacement element being translatory movable relatively to another element. First ends of first radiation conductors are fixed to the first translatory displacement element and first ends of second radiation conductors are fixed to the other element, wherein the first and the second radiation conductors are connectable to each other in different constellations through translatory movement of the translatory displacement element and the other element relative each other in order to obtain different operation modes of said system.

Abstract: A method of treating microbial infections, which consists of the steps of sequentially and repeatedly irradiating the microbe with continuous or pulsed infrared radiation and continuous or pulsed cooling such that heat and cold alternatively penetrates to the site of the infection in order to inactivate the pathogen.

Abstract: A radio frequency diathermy application device, including a flexible pad and a flexible coil structure coupled to and supported by the pad The flexible coil structure has a flexible spiral-like primary winding and a flexible spiral-like secondary winding coupled to the primary winding, the primary and secondary windings each substantially lying in separate substantially parallel planes when the pad is in an unflexed state.

Abstract: The present invention provides a system for increasing skin rejuvenation of a region of a patient's skin comprising a pulsed electromagnetic field (PEMF) frequency generator for constantly providing electromagnetic pulses to said region of a patient's skin and a deep tissue diathermy device for constantly applying heat to said region of a patient's skin up to temperature T. The system is adapted for simultaneously applying heat and PEMF to the region of a patient's skin,—wherein application of the system increases skin rejuvenation such that the skin rejuvenation increase (SRI) is greater than the sum of the SRI provided by electromagnetic pulses increase and the SRI provided by the deep tissue diathermy device increase.

Abstract: The present invention provides devices and methods for the treatment of atrial fibrillation. In one embodiment a deflectable sheath catheter includes an elongate catheter body having proximal and distal ends, the distal end having a distal tip region that includes a plurality of flexible segments with varying degrees of stiffness. A handle portion can be located at the proximal end of the catheter body to provide a steering mechanism that causes the distal tip region to deflect according to a compound curve.

Abstract: Apparatus for detecting vulnerable plaques embedded in the wall of a patient's blood vessel includes an intravascular catheter containing a microwave antenna, an extracorporeal radiometer having a signal input, a reference input and an output, a cable for electrically connecting the antenna to the signal input, and a device for applying an indication of the patient's normal tissue temperature to the reference input so that when the catheter is moved along the vessel, the locations of the vulnerable plaques are reflected in a signal from the output as thermal anomalies due to the higher emissivity of the vulnerable plaques as compared to the normal tissue. A second embodiment of the apparatus has two coaxial antennas in the catheter serving two radiometers. One measures the temperature at locations in the vessel wall, the other measures the temperature at the surface. By subtracting the two signals, the locations of vulnerable plaque may be visualized.

Abstract: A method of using a stimulation device to emit a medium to an appendicular region and/or rectal region of a user for treatment of a gastrointestinal disorder is described. The method includes placing the stimulation device into the appendicular region and/or rectal region, and delivering the medium, wherein the medium stimulates at least a portion of the enteric nervous system. Additionally, apparatus and delivery devices are disclosed.

Abstract: This invention provides methods for treating a variety of disorders using localized electromagnetic radiation directed at excitable tissues, including nerves, muscles and blood vessels. By controlling the wavelength, the wavelength bandpass, pulse duration, intensity, pulse frequency, and/or variations of those characteristics over time, and by selecting sites of exposure to electromagnetic radiation, improvements in the function of different tissues and organs can be provided. By monitoring physiological variables such as muscle tone and activity, temperature gradients, surface electromyography, blood flow and others, the practitioner can optimize a therapeutic regimen suited for the individual patient.

Abstract: This invention provides methods for treating a variety of disorders using localized electromagnetic radiation directed at excitable tissues, including nerves, muscles and blood vessels. By controlling the wavelength, the wavelength bandpass, pulse duration, intensity, pulse frequency, and/or variations of those characteristics over time, and by selecting sites of exposure to electromagnetic radiation, improvements in the function of different tissues and organs can be provided. By monitoring physiological variables such as muscle tone and activity, temperature gradients, surface electromyography, blood flow and others, the practitioner can optimize a therapeutic regimen suited for the individual patient.

Abstract: An apparatus for increasing the blood perfusion in skin by elevating the temperature, and for providing superior heat sinking to the skin of thermally dissipative devices is disclosed. The increased perfusion gives rise to improved thermal transport properties near the site of elevated temperature which is advantageously used by thermally connecting the dissipative devices to the skin. The heat generated by the thermally dissipative devices can supplement or replace separate heating elements to elevate the skin temperature. Alternatively, thermal isolation of the heated area of the skin from the heat sinks of the dissipative devices can minimize the temperature of the skin in contact with the heat sinks.

Abstract: A novel femtosecond laser nano-ablation technique called Plasmonic Laser Nano-Ablation (PLN). The technique takes advantage of surface-enhanced plasmonic scattering of ultrashort laser pulses by nanoparticles to vaporize sub-cellular structures in attoliter volumes. The use of nanoparticles may overcome problems associated with current FLMS techniques and does not rely on heating for nanodisruption. In PLN, the particle acts as a “nano-lens,” restricting laser light to the near-field of the particle, and only photodisrupting structures that are nanometers away. This eliminates the need for a tightly focused beam, while still achieving nanoscale ablation resolution. Moreover, the enhanced scattering around the particles reduces the amount of required laser fluence.

Abstract: A method and apparatus (100) of treating tissue adjacent a bodily conduit using thermotherapy, while preventing obstructions of the bodily conduit due to edema, includes injection of a drug-encapsulated within a heat-sensitive carrier, such as a liposome, within a region of tissue to be treated. The heat produced by the energy-emitting source (110) heats a portion of the tissue surrounding the bodily conduit to a temperature of approximately 43° C. for a time sufficient to destroy the heated portion of the tissue. In addition, the heat produced by the energy-emitting source (110) activates the heat-sensitive carrier to activate the release of the encapsulated drug and the drug targets the tissue to be heated. The focused energy of the energy-emitting source together with the compression acting on the target area can assist in delivering drugs to the target area so that a natural stent has a long term efficacy.

Abstract: A capsular device for esthetic and therapeutic treatment, but particular involves a device for body treatment that allows emission of infrared together with negative ions, allowing easy elimination of toxins, heavy metals, preventive control of some diseases and postsurgical therapeutic treatment; said capsular device has a fixed structure equipped with a rail on which a perpendicular mobile chamber is mounted, which is made up of an individual base configured by seat and back, said base having protective side arms and articulated cover with control panel with computer screen and screen with images of the patient, which enable constant follow-up of measurement variations.

Abstract: Described are dental implements useful for inspecting tooth surfaces for abnormalities such as caries or plaque. Preferred implements of the invention include light-emitting diodes mounted on an implement body having a mirror for insertion into a user's mouth. Such implements also have on-board batteries mounted in chambers in the implement handle, and a switch for energizing and de-energizing the LED with the battery. Also described are methods for examining tooth surfaces for abnormal conditions indicative of plaque involving illuminating surfaces with radiation at a wavelength in the range of 390-450 nm wherein the radiation is effective to cause detectable fluorescence emissions from bacterial metabolites known to be associated with plaque-containing surfaces, and detecting the emissions.

Abstract: A method and apparatus for treating gland dysfunction caused by gland obstruction in order to restore the natural flow of secretion from the gland comprises the application of a combination of energy, suction, vibration, heat, aspiration, chemical agents and pharmacological agents to loosen and thereafter remove the obstructive material.

Abstract: A therapeutic heating pad which is not hot to the touch provides substantial infrared radiation to a user. Accordingly it can be used for extended periods without feeling uncomfortable to the skin, while imparting deep therapeutic heat to the user. The heating pad is comprised of a radiant heat generating layer having a plane surface comprising means for radiating heat evenly from its surface, a pair of flexible electrically insulating and radiation permeable layers located adjacent and covering opposite sides of the layer, a thermal insulation layer disposed against and covering one of the electrically insulating layers, and a sealed radiation permeable envelope enclosing the entire heater. Preferably the flexible heat generating layer is comprised of a fiberglass material impregnated with a resistive material, which material provides a surface temperature, when current is conducted therethrough, which is no greater than about 54 degrees Celsius.

Abstract: A novel bulb and bulb assembly. In an embodiment, the present invention comprises a shell enclosing a hollow interior, and a tube intersecting with the shell such that the ends of the tube reside outside the shell and a portion of the tube resides within the shell. Each intersection of the tube and the shell in this embodiment is accomplished so that any contents of the hollow interior of the shell are sealed within the shell and any contents of the hollow interior of the shell are segregated from any contents of the portion of the tube residing within the shell. This embodiment may further comprise at least one electrode having at least one end terminating inside the shell. This embodiment may further comprise a source of electromagnetic waves positioned such that electromagnetic waves emanating from the source of electromagnetic waves pass through the shell.

Abstract: Medical catheter apparatus for minimally invasive applications includes a probe for radiating electromagnetic waves of a first frequency capable of heating tissue and detecting thermal emissions from that tissue of a second frequency indicative of tissue temperature. The probe has an inner conductor extending along the probe to a conductive probe tip and a concentric tubular outer conductor having a leading end spaced rearwardly from the probe tip and a closed trailing end shorted to the inner conductor. A dielectric sheath surrounds the outer conductor which sheath has a leading end spaced rearwardly from the leading end of the outer conductor. A diplexer integrated into the probe includes a filter circuit positioned inside the outer conductor and a coupling capacitor connected between a point on the inner conductor and the input of the filter circuit such that the conductors between that point and the shorted trailing end of the outer conductor constitute a quarter wave stub at the second frequency.

Abstract: An applicator and method for application of electromagnetic energy to an area of tissue is described. The applicator includes a visually-transparent, high-dielectric interfacing assembly which has a conformable tissue-engaging surface and an opposed antenna-engaging surface. At least one balanced, circularly-polarized antenna is disposed in a plane substantially parallel and adjacent to the antenna-engaging surface. The interfacing assembly and at least one antenna are substantially transparent to enable visual viewing of the area of tissue. This enables monitoring of the tissue for adverse treatment effects while electromagnetic energy is being applied to the at least one antenna and radiated into the tissue.

Abstract: An infrared radiant heating system for raising or maintaining a uniform core temperature of the body of a patient during surgery, substantially without affecting the temperature of the area surrounding the patient's body, comprising: infrared radiant heating means which in use is located in an unobtrusive position near the patient to provide radiant heat to the entire body or one or more parts of the body of the patient; and control means in communication with the heating means for controlling the intensity level and distribution of intensity of the radiant heat on the patient's body such that in use the skin temperature of the patient's body is raised or maintained within a predetermined range resulting in the uniform core body temperature, substantially without affecting the temperature of the area surrounding the patient's body.

Abstract: A radiant therapeutic wrist heating pad, which is not hot to the touch, provides substantial infrared radiation to a user's wrist to alleviate symptoms of carpal tunnel syndrome. It can be used for extended periods without feeling uncomfortable to the skin, while imparting deep therapeutic heat to the user's wrist. The heating pad is comprised of a radiant heat generating layer having a plane surface comprising means for radiating heat evenly from its surface, a pair of flexible electrically insulating and radiation permeable layers located adjacent and covering opposite sides of the layer, a thermal insulation layer disposed against and covering one of the electrically insulating layers, and a sealed radiation permeable envelope enclosing the entire heater.

Abstract: A method wherein, following a therapeutic radiation treatment, a heat dose is administered to the treated cells to decrease the damage caused by radiation exposure or a therapeutic agent.

Abstract: A method and system for selective heating of an object based on a model of the object, the method comprising the steps of: modeling of a wave front of a source, which wave front is propagated through the model object from a virtual antenna placed in the model of the specific region where heating is desired, simulating a radiated field and measuring the same using computer models of surrounding antenna system, time-reversing, transferring and synthesizing the signal in a real system, transmitting by a real antenna system the field in a time reversed order, and refocusing of time reversed signal at the original s the invariance of a wave equation under time reversal.