System that controls electric power with respect to antenna array having different loads

Abstract

To provide a system capable of adjusting an electric power output and a phase from a single transmitter so as to be used in an antenna array in which loads to respective antennas may be greatly different from each other.SOLUTION: An antenna system includes an array of antennas. Each antenna discharges an electromagnetic wave and a load different from that of other antennas in the array is applied to each antenna. The antenna system further includes a control system. The control system includes: a single transmitter that sequentially drives an antenna set; a switching device that selects an antenna set to be driven for each activation period in an activation sequence; and a controller. The controller determines an actual electric power output of each antenna, and generates an adjustment control signal with respect to the single transmitter such that an output of each antenna is controlled to match a target power of the antenna irrespectively of the load to the antenna.SELECTED DRAWING: Figure 1

Description

Background Art

[0001] Background

[0001] Someone in the world suffers from Alzheimer's disease (AD) every three seconds. AD, the most common dementia, is a debilitating neurodegenerative disorder that experiences confusion, memory impairment, language impairment, and decline in physical function, and often becomes completely dependent on others within 4 to 5 years after diagnosis. AD is the cause of one-third of the deaths of the elderly and claims more lives than the combination of breast cancer and prostate cancer. Today, it is estimated that more than 50 million people worldwide are living with AD, and the number of patients is increasing at an alarming rate and is expected to double in the next 30 years.

[0002]

[0002] Conventionally, pharmaceutical companies have been pouring research efforts into AD. However, after hundreds of billions of dollars of research, AD remains unpreventable, incurable, or unable to be further delayed. An effective treatment or cure for AD is estimated to be worth more than $20 billion annually. Sadly, no product has been proven to cure the disease or further delay its progression.

[0003]

[0003] Similarly, other neurodegenerative diseases and neurological conditions are plaguing society with current treatments and / or cures that have been found to be ineffective.

[0004] Brief Description of the Drawings

[0004] The accompanying drawings illustrate various examples of the principles described herein and are part of the specification. The illustrated examples are provided for illustrative purposes only and do not limit the claims.

Brief Description of the Drawings

[0005]

Figure 1

[0005] A block diagram of an antenna system according to an example of the principles described herein.

Figure 2

[0006] A block diagram of an antenna system according to another example of the principles described herein.

Figure 3

[0007] An antenna system according to an example of the principle described herein is shown.

Figure 4

[0008] An antenna system according to another example of the principle described herein is shown.

Figure 5

[0009] A flowchart of a method for controlling an antenna system according to an example of the principle described herein.

Figure 6

[0010] An example of a switching device for selecting, controlling power and phase of an antenna according to an example of the principle described herein is shown.

Figure 7

[0011] A flowchart of a method for controlling an antenna system according to another example of the principle described herein.

Figure 8

[0012] An electromagnetic therapy device having an antenna system according to an example of the principle described herein is shown.

Embodiments for Carrying Out the Invention

[0006]

[0013] Throughout the drawings, the same reference numerals indicate similar (but not necessarily identical) elements. The drawings are not necessarily to scale, and the sizes of some parts may be emphasized to show the illustrated examples more clearly. Further, the drawings provide examples and / or implementation forms that are consistent with the specification. However, the specification is not limited to the examples and / or implementation forms provided in the drawings.

[0007] Detailed Description

[0014] As described above, AD is a neurodegenerative disease that affects millions of lives and for which no drug cure or treatment has been found. In cases where pharmaceutical solutions do not work, an innovative medical device as described herein that uses transcranial electromagnetic therapy (TEMT) provides a solution. This device holds the potential to slow down and / or reverse the effects of AD. The device includes a cranial cap with multiple radio wave transmitting antennas fixed to a control box worn on the arm. In some examples, the antennas may transmit high frequencies. However, in other examples, electromagnetic waves may be applied at other frequencies. In these other examples, the system may include other components (e.g., coils or contact patches instead of antennas). The control system may further include different components and may be placed at different locations on the patient's body. The treatment may be administered at home by the patient's caregiver rather than at an outpatient facility. The device herein is the only technology under clinical development that targets both of the putative causes of AD (the accumulation of small beta-amyloid (Aβ) oligomers and tau oligomers within neurons). Extensive preclinical studies have shown that the TEMT device has beneficial cognitive effects associated with the breakdown of toxic protein oligomers (especially Aβ) and the improvement of brain mitochondria in animal models of Alzheimer's.

[0008]

[0015] While specifically described for AD, further, the system is for the treatment of other neurodegenerative diseases or neurological conditions (e.g., mild cognitive impairment (MCI), mixed AD / vascular dementia, cerebral amyloid angiopathy, intracerebral hemorrhage, multi-infarct dementia, Parkinson's disease, Lewy body dementia, Down syndrome, traumatic brain injury, frontotemporal dementia, post-traumatic encephalopathy, Huntington's disease, or prion diseases (hereditary spongiform encephalopathy, kuru, and Creutzfeldt-Jakob disease), amyotrophic lateral sclerosis (ALS), mental retardation, stroke, autism, bipolar disorder, schizophrenia, anxiety disorder, mitochondrial encephalomyopathy, epilepsy, migraine, major depression, dystonia, and hemiballismus, age-associated memory impairment (AAMI), normal / non-declining cognitive function, or below-normal cognitive function).

[0009]

[0016] To perform whole-brain TEMT, the device provides sequential activation of multiple antennas positioned within the head unit such that only one antenna is active at any given time. Treatment may be applied if the antennas are continuously active. However, in some instances, pulsed energy may be more effective. Based on this more effective treatment, to maximize treatment to multiple regions of the brain, the present array system and electromagnetic treatment device pulse the energy to multiple antennas distributed around the patient's head. Since pulsed treatment includes an active transmission period and an idle period, the antenna system utilizes the idle time for one antenna to activate another antenna. As a specific example, for an antenna system having N antennas, if the active time for each antenna is 1 / N, the idle time outside of this active time can be used to activate other antennas, multiplying N by the areas of the brain that can be treated in the same treatment session. Operating the antenna system in this way maximizes the coverage of the brain. However, more focused deeper treatment may be required in specific regions of the brain. This deeper penetration can be achieved simply by simultaneously activating two or more antennas that are transmitting the same waveform. When multiple antennas are effectively transmitting the same waveform, the propagating waves are summed in the radiation field, generating a peak in a specific region within the radiation field. Thus, the treatment energy can be focused on a specific region of the brain. By changing the phase of the signal for each active antenna, the location of the peak can be moved, steered, or focused to a specific location. This is called beamforming. The combination of multiple antennas and beamforming capabilities can fully cover all regions of the brain.

[0010]

[0017] For the practical use of a treatment device as described, the control system that generates the treatment waveform used for treatment should be made as small as possible so that the patient can wear the device and move around while wearing it. A lower-cost treatment device expands treatment options to more patients.

[0011]

[0018] To achieve the goals of being smaller and lower cost, integration and reuse of the electronic circuits within the control unit are desirable. This affects every aspect of product design, but presents challenges along the way as there is currently no circuit design that addresses the unique problems arising from the implementation of devices with TEMT unit requirements.

[0012]

[0019] A small, low-cost TEMT unit facilitates the need for the control unit to use a single transmitter and distribute the output of that transmitter to each antenna at the appropriate times, or in the appropriate combinations of power levels and phases. This architecture is preferable to an architecture that uses dedicated transmitters for each antenna when considering the design goals of smaller size and lower cost.

[0013]

[0020] However, driving different antennas from a single transmitter presents challenges of its own. The biggest challenge is the power control of the transmitter. The transmission system is designed to radiate a predetermined power level from the antenna regardless of the load on the antenna. When the load on the antenna changes, the load on the transmitter also changes, and the transmitter needs to operate better under some load conditions to maintain the same output power level. In the example of a single antenna scenario, a control loop monitors the output power of the transmitter and adjusts the power level control for the transmitter while keeping the output power constant. This control loop may have a damping response and prevent the output power level from oscillating. Generally, the load on the antenna changes relatively slowly because the elements change spatially near the antenna. Therefore, it is advantageous to change the power control slowly to maintain the stability of the output power level.

[0014]

[0021] When driving multiple antennas with the same transmitter, each antenna may have a different load applied to it, which means that the power output control of the transmitter needs to vary for each antenna when the transmitter drives the antenna. In other antenna arrays, the antennas within the array are generally mounted together, and any material in proximity to one antenna is in proximity to the entire array, so the loads of the antennas within the array are very similar and there is no problem.

[0015]

[0022] Each antenna in the head unit presents unique challenges because each antenna has a very different load based on how it is positioned relative to the patient's head, scalp, and hair. As a specific example, a patient with a large amount of hair can wear the head cap of the TEMT device while sitting in a reclining chair with the back of the patient's head pressed against the reclining chair. In this scenario, the antennas at the back of the head are very close to the material in the reclining chair, and as a result, the load on those antennas changes. At the same time, the pressure exerted on the reclining chair compresses the patient's hair, bringing those antennas closer to the scalp. Thus, the antennas at the back of the head have the scalp on one side and the reclining chair very close on the other side. In contrast, the antennas on the front of the head are held slightly away from the scalp by the patient's hair and there is free space outside the antennas because there is nothing in front of the head. Thus, in this example, the antenna loads between the front and back antennas are significantly different, and the transmitter should operate at different levels to generate the same output power between the antennas despite the difference in load. The loads in the TEMT device can be very significantly different from the loads seen in other antenna array systems. In current implementations, the significantly different loads between the antennas within the array, such as those that occur in the TEMT device, are not taken into account.

[0016]

[0023] In the sequential activation of the antenna, the time to adjust the output power level of the transmitter comes during the short period when the antenna is being switched. Next, once the switching is complete, the power control should again have an attenuation response to stabilize the output power level. This combination is difficult to achieve in an inexpensive way that does not add significant complexity to the implementation circuit.

[0017]

[0024] Accordingly, this specification describes a small, low-cost system that can adjust the power output and phase from a single transmitter for use in an antenna array where the load on each antenna can vary significantly.

[0018]

[0025] This specification describes systems, methods, and devices for addressing problems such as those described above. Specifically, this specification describes a method of power control that can keep the amount of power applied to an antenna that is sequentially switched constant, even when the antenna load varies.

[0019]

[0026] Specifically, this specification describes an antenna system. The antenna system includes an array of antennas each emitting an electromagnetic wave. In this example, each antenna has a different load applied to it than the other antennas in the array. The antenna system further includes a control system. The control system includes 1) a single transmitter that drives the antenna sets sequentially, 2) a switching device that selects the antenna set to be driven for each activation period in the activation sequence, and 3) a controller. The controller determines the actual power output of each antenna for each activation sequence and generates an adjustment control signal for the single transmitter such that the power output of at least one antenna is the same as the average value, regardless of the load on the antenna.

[0020]

[0027] Furthermore, this specification describes a method. According to the method, for each antenna in an array of antennas, a difference between the actual power output for each antenna and the average power output across the array of antennas is determined. Regardless of the load on the antenna, a control signal for a single transmitter coupled to each antenna in the array is adjusted so that the power output of at least one antenna is the same as the average power output across the array. At least one antenna is driven by the single transmitter based on a first adjustment control signal.

[0021]

[0028] Furthermore, this specification describes an electromagnetic therapy device. The electromagnetic therapy device includes a head unit that holds an antenna at a predetermined position relative to the head. The head unit further includes an array of antennas each emitting an electromagnetic wave. In this example, a different load is applied to each antenna depending on how each antenna interfaces with a corresponding portion of the head. The electromagnetic therapy device further includes a control system including: 1) a single transmitter that drives the antenna set; 2) a switching device that selects the antenna set to be driven for each activation period in an activation sequence; and 3) a controller. For each activation sequence, the controller: 1) determines the actual power output when driving each antenna, and 2) generates an adjustment control signal for the single transmitter so that the power output of at least one antenna is the same as the average power output across the array regardless of the load on the antenna.

[0022]

[0029] As used in this specification and the appended claims, the term "activation period" means different points in time when a particular antenna or group of antennas is active.

[0023]

[0030] Further, as used in this specification and the appended claims, the term "activation sequence" means a sequence or pattern of activation periods. Over the entire activation sequence, each antenna may be activated once. In some examples, for a single activation sequence, only one activation period has an adjustment control signal, and the other activation periods do not have an adjustment control signal.

[0024]

[0031] Further, as used in this specification and the appended claims, the term "treatment session" means a plurality of activation sequences that are sequentially executed. The length of the treatment session may be determined by a caregiver.

[0025]

[0032] Further, as used in this specification and the appended claims, the term "target value" means a desired output power value of the antenna based on a treatment parameter.

[0026]

[0033] Further, as used in this specification and the appended claims, the term "average power" means the average power output across the antenna array, and may vary for each activation sequence. For each activation sequence, the power output of at least one antenna is adjusted to match the average power.

[0027]

[0034] As described, the antenna system may activate one or more antennas at a given time. In some cases, by changing the phase and / or power of multiple or single antennas, the system can focus an energy beam on a specific brain region. By activating multiple antennas sequentially as groups or simultaneously, a more focused and powerful treatment can be performed.

[0028]

[0035] To address the above problems, this specification describes a power and phase control mechanism that applies the output power from a single transmitter (which may be an RF or other type of transmitter) to an array of antennas where the output load can vary significantly from one to another. Such a power control mechanism provides a consistent radiated output power level from antennas that may be subject to different loads, even with a high-speed sequential switching time from one antenna (or group of antennas) to the next.

[0029]

[0036] A TEMT device for the treatment of Alzheimer's disease and other diseases and conditions incorporating this system is a device that includes an electronic control system and a head unit having a plurality of individual antennas that radiate electromagnetic waves (e.g., radio frequency) into the brain. These antennas can be activated sequentially and / or in combination to generate a radiation pattern used as a treatment for the brain. The amount of power radiated from each antenna can be controlled to match the prescribed treatment and not be too little or too much compared to what is desired.

[0030]

[0037] To achieve a controlled output power level from the antennas, the system may include a variable output transmitter. The output power of the transmitter may be controlled via a power control signal, and as a result of changes in this signal, a corresponding change in the output power of the transmitter is obtained. When this control signal is held constant, the output power of the transmitter remains constant as long as the load applied to the transmitter by the antennas remains the same.

[0031]

[0038] However, for example, when the load of the antenna changes due to physical proximity to an absorbing or reflecting substance, the load applied to the transmitter also changes. If the control signal is kept constant, the output power will change depending on this load. This is because, to drive a certain load, the transmitter outputs a different power level than when driving other loads with a constant control signal. Therefore, to keep the antenna output constant, the transmitter can use this control signal to change the strength with which the transmitter is driven in response to changes in the load. To achieve this operating mode, the system may use a power coupler or detector that senses the amount of power coming out of the transmitter and changes the control signal until the target output power is reached. In this method, when the load of the antenna changes and the output power changes due to the load, the control signal is adjusted so that the output power is maintained at the target level.

[0032]

[0039] However, in such a system, since the transmitter can respond very quickly to changes in the control signal, it is very easy to create a situation where the change in the control signal amplifies the change in the output power too much. The power detector detects this and changes the control signal, resulting in oscillations in the power output level. To prevent such a scenario, the circuit may include an attenuation function that ensures that the adjustment settles towards the target output without overshooting the target output power and instead without oscillating. This attenuation function can be achieved by adding a low-pass filter to the feedback loop driving the control signal.

[0033]

[0040] However, such control feedback may not be able to address the operating states of TEMT devices as described herein. This problem occurs when using a single transmitter and power control loop to maintain a constant power output level while rapidly changing the driven antenna. That is, in a non-TEMT antenna array, since the antennas in the array are loaded in the same way, the power control signal used during the transmission of one antenna generates the correct power output for all antennas in the array, enabling power control across the entire array rather than for each individual antenna.

[0034]

[0041] Now, the drawings will be described. FIG. 1 is a block diagram of an antenna system (100) according to an example of the principles described herein. The antenna system (100) includes an array (102) of antennas (104). Each antenna (104) emits electromagnetic waves. As described above, TEMT devices as described herein operate in a unique way where the antennas (104) are placed at various positions on a patient's head, being very close to the scalp at some positions while being away from the scalp due to hair volume at other positions. Accordingly, the load applied to each antenna (104) is very different from the other antennas (104) in the array (102), and very different control signals should be provided to the transmitter (108) when activating each antenna (104).

[0035]

[0042] Further, the antenna system (100) includes a control system (106) including a single transmitter (108) that sequentially drives a set of antennas (104), and a switching device (110) that selects the set of antennas to be driven for each activation period in the activation sequence. Further, the antenna system (100) includes a controller (112) that: 1) determines the actual power output of each antenna (104) when a given current load is applied, and 2) generates an adjusted control signal for the single transmitter (108) such that the output of at least one antenna is the same as the average power output across the array regardless of the load on the antenna (104). The controller (112) may sequentially determine the actual power output of each antenna (104) and generate an adjusted control signal for the single transmitter (108) until each antenna (104) within the array (102) has a power output that matches the target value regardless of the load on the antenna (104).

[0036]

[0043] In one particular example, the TEMT device has an antenna system (100) with eight antennas (104) and cycles through each antenna (104) at a rate of 217 Hz. This means that each antenna (104) is activated every 4.6 milliseconds (mS) and is on for a duration of 576 microseconds (μS). To maximize the effectiveness of a treatment session, it may be desirable to have a particular antenna (104) active 99% of the time, which means that the antenna (104) needs to be switched every approximately 5 μS. It is difficult to run a standard control loop at this timing using the filtering present in a typical controller and still maintain stability and prevent oscillations in the output power. However, the adjusted control signal generated by the control system (106) accounts for the load on the antenna (104) and generates the adjusted control signal during switching within the activation sequence.

[0037]

[0044] To achieve different power control for individual antennas (104) with high-speed sequential activation, the control system (106) may divide the power control loop into two loops. These control loops may be executed by components provided in the transmitter (108), the controller (112), or a combination thereof. In the first loop, the power control signal is adjusted based on the average power detected across all driven antennas (104). That is, the controller (112) gives a target power value to the first loop, and this loop adjusts the power control signal to match the average power to the target power. This first loop is, for example, a relatively slowly changing loop that adjusts to changes in the total power level caused by, for example, the antennas (104) changing their position relative to the patient's head.

[0038]

[0045] The second power control loop operates faster, compares the power detected for each antenna (104) with the average power detected in the first control loop, and identifies which antenna (104) produces the power level that is farthest from the average. Next, the second power control loop finely adjusts the power control signal used during the activation period of the identified antenna (104) to bring its power level closer to the average. In one example, only one adjustment is made during each activation sequence, and that adjustment is made only for the antenna (104) that produces the power farthest from the average detected power of all antennas (104). After many activation sequences and adjustments, all antennas (104) will eventually stabilize and produce an output as close as possible to the average power level. At this point, fine-tuning may still be done, and there is a possibility that the antennas (104) will fall into a pattern where they are adjusted in one direction in one treatment cycle and back in the other direction in the next treatment cycle. In another example, the control system (106) can adjust the antennas (104) until the detected power of the antennas falls within a threshold range away from the average power, at which point no further adjustment is made.

[0039]

[0046] To implement this second control loop, a power control signal offset needs to be maintained for each antenna (104). Thus, during the process of executing this second control loop, when an antenna (104) is selected, the power control value for the first loop is adjusted by the power control signal of that antenna (104) offset from the second control loop, and that value is applied to the transmitter (108) for the duration that this antenna (104) is active, i.e., during the activation period of the antenna. Thereafter, this control is repeated for each antenna (104).

[0040]

[0047] In an alternative embodiment, the second control loop operates fast enough to adjust the power control signal at the beginning of the activation period to enable accurate power control early within the activation period. In yet another embodiment, the second control loop can operate even faster at the beginning of the activation period, but slows down as the output power of the current antenna set approaches the average power. The adjustment of the loop speed is the adjustment of the loop's low-pass filter or the loop's attenuation response.

[0041]

[0048] In one embodiment, the first control loop is not executed, and the second control loop becomes the main power control loop, directly controlling the power output of each antenna set during the activation period of the antenna set. In this embodiment, the power output for the antenna set is measured by a coupler (328) and compared with the target output by a controller (112). The difference between the actual power and the target power is used to determine an offset, and the offset is used to adjust the activation sequence power control signal when the antenna set is set up in the next activation sequence. This process is repeated for each activation period in the activation sequence, and then repeated for each activation sequence in the treatment session.

[0042]

[0049] In one embodiment, a second control loop can be used to perform factory calibration that accounts for differences in transmit path loss through the switching device (110) to each antenna (104). This can be done using an initial offset value for each antenna (104) that is loaded with a value calculated at the time of manufacture after measuring the specific path loss in the path to each antenna (104). In another example, the calibration value calculated at the time of manufacture can be used as an additional offset to the value measured by a power detector for each antenna (104).

[0043]

[0050] In yet another example, it may be desirable to drive each antenna (104) at different transmit power levels. The different power levels are desirably based on the location of that antenna (104) relative to the desired treatment area based on anatomical or experimental data indicating the need for different treatment levels. In this embodiment, instead of calculating an average value across all antennas (104), i.e., a first control loop, a second control loop is used to control the power output of each antenna (104) by comparing it to the target output level of that antenna (104).

[0044]

[0051] In yet another example, a first control loop is used to determine an average output power value across the array (102). However, the second control loop makes adjustments to keep a few antennas (104) transmitting at power levels higher or lower than the calculated average value.

[0045]

[0052] As described herein, the output of the second control loop may influence or change the power control voltage of the first control loop. In one particular example, the output of the second control loop can be supplied to a different part of the circuit. In one particular example of such a case, the first control voltage is supplied to the final power amplifier of the transmitter (108), and the output of the second control loop is used to change the RF input power level to the final power amplifier.

[0046]

[0053] The description up to this point has focused on the sequential activation of the antenna (104). In this mode, a single antenna (104) is active at a given time. That is, the set of antennas to be activated includes a single antenna. In this example, the selection of the antenna (104) can be performed by a 1-to-N switching device (110). In such a switching device (110), each of the N switches connects a common input to each antenna (104) in the antenna array (102). The control signal coming into the switching device (110) identifies which output should be active, sets that switch to the closed position, and connects the common input to the selected output. Examples of switching devices (110) include PIN diodes, transistors, microelectromechanical systems (MEMS), or other devices that selectively pass or block RF signals.

[0047]

[0054] In other examples, the set of antennas includes multiple antennas (104). To drive multiple antennas (104) simultaneously to direct RF treatment to a specific location, the switching device (110) can have more than one switch active at the same time and divide the power from the transmitter (108) among the active antennas (104). As will be described below, in such an example, the switching device (110) may perform impedance matching to maintain the appropriate impedance presented to the transmitter (108). In this example, instead of the sequential activation of individual antennas (104), there is sequential activation of groups of antennas (104). In this example, at least one of the quantity and index of the antennas (104) in the set of antennas may change for each activation sequence. For example, the sequence may first activate antennas 1 and 3, then antennas 2 and 4, then antennas 1, 2, and 3, then antenna 5, then antennas 6 and 7, then antennas 5 and 7, then antennas 5 and 6, and finally antenna 8.

[0048]

[0055] During each step of the sequential activation of the antenna set, both of the above-described power control loops may be in operation using a first control loop that maintains the average power and a second control loop that adjusts for each antenna set.

[0049]

[0056] Similar to the sequencing of a single antenna (104), the sequencing of multiple antenna sets may have different target output levels for each antenna set. This is because, in order to obtain the desired effect, the set of antennas (104) can be driven at different power levels than a single antenna. Further, when power is divided among multiple antennas (104) in a set, the power in each antenna (104) decreases. Accordingly, the controller (112) may increase the power of the transmitter (108) to compensate for this power loss. Accordingly, in one example, each antenna set may be adjusted towards a different target output level.

[0050]

[0057] Since the antenna system (100) enables independent power control between each antenna (104) in the array (102), the power control executed by the control system (106) can detect whether there is a problem with a single antenna (104) in the array (102) and take appropriate measures. In one embodiment, the control system (106) may, for example, detect one of the antennas (104) that is not properly connected, and as an example, when the antenna (104) appears in the sequence, that antenna (104) may not be used and other antennas (104) in the array (102) may continue to be used. This is beneficial because in the case of a damaged or disconnected antenna (104), the high-power transmitter may be damaged.

[0051]

[0058] In some examples, simply placing tolerance operating limits around the power control parameters can detect errors, and if those limits are exceeded, the errors are reported. This error condition may be shown to the user via the user interface, may be logged as an error, or may be processed in other ways. Alternatively, the control system (106) can interrupt all treatments upon detection of an error in a single antenna (104) and can indicate the problem in any of the described ways.

[0052]

[0059] In another example, rather than driving power in parallel with the antenna (104), it is desirable to ensure that each antenna (104) in the set is radiating at the same power level, and it is desired that the radiated power be the same among the antennas (104). In this example, the control system (106) may include dedicated power detectors after switching for each antenna path and variable attenuation devices. In this example, the control system (106) monitors the power levels at each antenna (104) and attenuates the antenna (104) with a higher power output until all antennas transmit at the same power. This control loop may operate in conjunction with the above-described control loop that provides a power control signal to the transmitter (108).

[0053]

[0060] Using a transmitter (108) that drives several antennas (104) in the set, all antennas (104) within the set are radiating at the same power level and focusing the treatment energy on a desired region within the brain. In some examples, to move the location of the focus within the brain, the controller (112) changes the phase of the treatment supplied to one or more of the antennas to steer the beam. A dedicated phase-shifting network for each antenna can be used to change the phase of the signal supplied to each antenna (104).

[0054]

[0061] In this last example, the functionality of the switching device (110) may be increased via a combination of switches / attenuators / phaseshifters. In one embodiment, power level detection for a particular antenna path may be further combined with each switch, such that for each antenna path there is a combination of switch / attenuator / phaseshifter / power detector.

[0055]

[0062] Although FIG. 1 shows a particular configuration, it will be apparent to those skilled in the art that variations in the implementation of these schemes, including the location of circuits within the unit and details of other implementations, are further included within the full principles as described herein.

[0056]

[0063] FIG. 2 is a block diagram of an antenna system (100) according to another example of the principles described herein. As described above, the antenna system (100) may be implemented with a transcranial electromagnetic therapy (TEMT) device and includes a control system (106) that drives an array (102) of eight antennas (104) in a head cap worn by a patient undergoing treatment. This drawing shows three components of the antenna system (100), which are the control system (106), the antenna array (102), and an AC-DC adapter (222) that is plugged into a wall and charges the control system (106). During treatment, the head unit provided with the array (102) may be worn by the patient, and the control system (106) may be attached to the patient's arm using, for example, a strap with hooks and fasteners. During treatment, the control system (106) is connected to the AC-DC adapter (222) for charging.

[0057]

[0064] The control system (106) includes a controller (112) that manages therapy, schedules, and the user interface. During therapy, the controller (112) enables the transmitter (108) to generate and amplify a desired RF waveform according to the therapy parameters. Next, the power amplifier (PA) of the transmitter amplifies the RF signal to the level required for therapy. The PA output is supplied to the switching device (110) to direct the RF signal to the appropriate antenna (104) within the antenna array (102) installed in the head unit. As described above, the switching device (110) can have a pure switching function, but can also control power and control the phase for different antennas in the antenna array (102). That is, the controller (112) may change at least one of the phases of the RF therapy for each antenna in the antenna set, and may change at least one of the powers of the RF therapy for each antenna in the antenna set to control the relative power between each antenna set. The control system (106) may include a control panel (214) that provides the user with an interface for starting or stopping therapy and provides the user with feedback and information (e.g., therapy status and battery level).

[0058]

[0065] The control system (106) may be powered by an internal battery (220) that runs the control system (106) and provides sufficient power to complete the therapy. The charging device (218) charges the battery (220) if an AC-DC adapter (222) is present. In one example, the controller (112) obtains the charge state and the presence of the AC-DC adapter (222) from the charging device (218) and displays the status on the control panel (214).

[0059]

[0066] Figure 3 shows an antenna system (100) according to an example of the principles described herein. In this example, the transmitter (FIG. 1, 108) includes an oscillator (324) that generates an RF signal. In one example, the oscillator (324) is a phase-locked loop, or PLL, that is modulated with a desired modulation. Next, the RF signal is supplied to a variable gain amplifier (VGA) (326) of the transmitter (FIG. 1, 108) and can be controlled in analog or digital mode. In an example, the variable gain amplifier (326) is digitally controlled by setting a value in a power control register within the transmit integrated circuit (IC). Next, the output of the variable gain amplifier (326) is supplied to a power amplifier (316) of the transmitter. This power amplifier (316) may be a high-power device that can be driven at the high output levels required for therapy. The output level of the power amplifier (316) should be accurately controlled by an active power control system (330) to ensure that the transmitter (FIG. 1, 108) always outputs a constant level regardless of the load applied to the transmitter (FIG. 1, 108). This is advantageous because if the load on the power amplifier (316) changes and the power is not adjusted accordingly, the power amplifier (316) may output a power level that exceeds the power amplifier's rating and may be damaged immediately. The output of the power amplifier (316), when radiated into the air, is supplied to the antenna (104) via a coupler (328).

[0060]

[0067] The power control system (330) controls the output power of the power amplifier (316) (circuit not shown) by measuring the output power via a coupler (328), rectifying the coupled power, and generating a voltage proportional to the output power. Next, this voltage is amplified by an amplifier (334), filtered through a first low-pass filter (336), and compared with a control voltage by a differential amplifier (338). The control voltage for comparison is generated from a control voltage generator (340) in the controller (112), and the control voltage generator (340) may be a power control digital / analog converter (DAC). The difference between the reference output power and the control voltage is filtered through a second low-pass filter (344) and supplied to the control input of the secondary amplifier (328). Although FIG. 3 shows a specific architecture for the power control system (330), the details of this power control device may be integrated, combined, or separated from each other in an actual implementation form. For example, the first low-pass filter (336) may be integrated with the amplifier (334) to generate an amplifier having a low-pass filtering response. Further, the power control system (330) may be provided in the transmitter (FIG. 1, 108) or the controller (112).

[0061]

[0068] The controller (112) further includes a VGA control signal generator. The controller (112) in FIG. 3 sets a transmitter (FIGS. 1, 108) that transmits at a specific power output level. For a specific output level, the controller (112) sets a variable gain amplifier (326) to a known output level. Thus, in this example, the VGA control signal generator is a fixed value control signal generator (342) that performs power control on the variable gain amplifier (326). In this example, the controller (112) performs open-loop power control in that there is no feedback to close the loop and it guarantees to maintain the output at a desired target output level. An alternative embodiment may have a closed power control loop that drives the variable gain amplifier (326) for the output set by the fixed value control signal generator (342). Based on the desired output level at the antenna (104) and the gain and efficiency performance of the power amplifier (316), the output of the variable gain amplifier (326) is set to a specific output level. Further, the controller (112) uses a control voltage generator (340), i.e., a power control DAC, to set the control voltage for the differential amplifier (338). Through calibration, the controller (112) knows which control voltage corresponds to which output power at the antenna (104).

[0062]

[0069] During operation, the controller (112) sets up the target output level at the antenna (104), and the power control device (330) maintains its power level at the antenna (104). As the load of the antenna (104) changes, the load applied to the power amplifier (316) changes, and based on the applied load and the characteristics of the transmitter (FIGS. 1, 108), the power level output by the power amplifier (316) is changed. As the power changes, the level from the power coupler (328) changes, supplying and changing the detected voltage entering the differential amplifier (338), and then changing the power control for the transmitter (FIGS. 1, 108) to return the output power of the transmitter to the target level with this new antenna (104) load.

[0063]

[0070] Figure 4 shows an antenna system (100) according to an example of the principles described herein. This drawing shows elements in addition to those found in Figure 3. Similar to Figure 3, an RF signal is generated by an oscillator (324), supplied to a variable gain amplifier (326), and then supplied to a power amplifier (316). The output power of the final transmitter (Figure 1, 108) is combined via a combiner (328) and supplied to a power control system (330), which operates in the same manner as described in Figure 3. That is, the combined output is rectified, amplified by an amplifier (334), sent through a first low-pass filter (336), supplied to a differential amplifier (338), compared with a control voltage filtered by a second low-pass filter (334), and supplied to the control input of the power amplifier (316).

[0064]

[0071] Figure 4 shows the output of the combiner (328) supplied to a switching device (110). The switching device (110) under the control of a controller (112) directs RF to one of the antennas (Figure 1, 104) in the antenna array (102). In another example, further, the switching device (110) can direct power to multiple antennas (Figure 1, 104) simultaneously, can adjust the power to each of the multiple antennas (Figure 1, 104), and can adjust the phase of the signal supplied to each of the multiple antennas (Figure 1, 104).

[0065]

[0072] The controller (112) switches the antenna (FIG. 1, 104) between inside and outside, so the power control system (330) maintains the average power across all antennas (FIG. 1, 104) to remain constant. However, this may be done for some of the antennas (FIG. 1, 104) with higher output power, while the other antennas (FIG. 1, 104) have lower output power, on the condition that the average of all antennas (FIG. 1, 104) is adjusted to a level corresponding to the control output by the control voltage generator (340). This is because the low-pass filtering in the first low-pass filter (336) and the second low-pass filter (344) results in a response that is slower than the time it takes to complete the antenna sequence. As a result, the power control system (330) averages the power levels of the entire antenna sequence.

[0066]

[0073] In this example, the controller (112) includes additional components and makes adjustments such that all antennas (Figure 1, 104) output at the same power level rather than at somewhat higher and somewhat lower power levels. The controller (112) achieves this by reading the detected power using a voltage detector such as a power detection analog / digital converter (ADC) (444) for each antenna (Figure 1, 104). If the detected output of a particular antenna (Figure 1, 104) is too high or too low, the variable gain amplifier (326) for that antenna (Figure 1, 104) is adjusted to bring its detected output closer to that of the other antennas (Figure 1, 104). Each time an antenna (Figure 1, 104) is enabled, the detected power is read by the ADC (444), the offset value for that antenna (Figure 1, 104) is calculated, and stored in an offset memory storage device (448) for that antenna (Figure 1, 104). For simplicity in Figure 4, only one offset memory storage device (448) is referenced by reference numeral. The next time the antenna (Figure 1, 104) is enabled, the VGA control signal generator (446) offsets the control signal for the variable gain amplifier (326) by the offset stored in the offset memory storage device (448) for that antenna (Figure 1, 104). Through each cycle of the antenna (Figure 1, 104), one or more offset values in the offset memory storage device (448) are calculated and adjusted. Through this process, after several iterations, the offset values settle to a final value and the power output across the antennas (Figure 1, 104) is equal.

[0067]

[0074] Once this second power control loop has settled, if the load on a single antenna (Figure 1, 104) changes, the power detection ADC (444) measures the corresponding power change and the controller (112) adjusts the offset value for that antenna (Figure 1, 104) until the output power of that antenna (Figure 1, 104) is returned to the same level as the other antennas (Figure 1, 104).

[0068]

[0075] For some reason, if there is a difference in loss between two different antenna paths through a switching device (110) or for routing on a printed circuit board (PCB), the controller (112) can store this loss as an additional offset value, and this offset can be used to offset all the readings of the power detection ADC (444) for that particular antenna (Figure 1, 104). By doing this, even if the path loss for each antenna (Figure 1, 104) is different, it can be ensured that the power output is the same for the antennas (Figure 1, 104).

[0069]

[0076] Figure 5 is a flowchart of a method (500) for controlling an antenna system (Figure 1, 100) according to an example of the principles described herein. According to the method (500), for each antenna (Figure 1, 104) in an array (Figure 1, 102) of antennas (Figure 1, 104), the difference between the actual power output for each antenna (Figure 1, 104) and the average power output across the array is determined (block 501). Note that in some examples, the average value used to compare the actual antenna power output in a single antenna is not the target value. That is, the target value is what the controller (Figure 1, 112) attempts to adjust the output power based on the treatment parameters. Next, the controller (Figure 1, 112) sets up a control loop to drive the antenna (Figure 1, 104) towards the target power. If the setup includes a single antenna system, that's all there is to it. However, in the case of a multi-antenna system, first, it is determined which antenna should be adjusted. Thus, the output of each antenna is compared to the average power output of all the antennas, not to the target power. In other words, the target power is the desired output based on the treatment parameters, and any adjustment is made to the antenna that is farthest from the average power (which may not be equal to the target power when the loop is tuned).

[0070]

[0077] After several activation sequences, the average power output should match the target power. However, since adjustments are being made, the average power may not be equal to the target power. Therefore, after driving at least one antenna (FIG. 1, 104) based on the first adjustment control signal, the method may include determining a new average power output across the array of antennas (FIG. 1, 102). Again, the controller (FIG. 1, 112) determines, for each antenna (FIG. 1, 104) in the array (FIG. 1, 102), the difference between the actual power output for each antenna (FIG. 1, 104) and this new average power output, and adjusts the control signal for the single transmitter (FIG. 1, 108) so that the power output of at least one antenna (FIG. 1, 104) is the same as the new average power output. The antennas (FIG. 1, 104) adjusted in the second activation sequence may not be the same as those adjusted in the first activation sequence. Next, based on the second adjustment control signal, the second antenna (FIG. 1, 102) is driven via the single transmitter. This process is repeated until the power output at each antenna (FIG. 1, 104) within the array (FIG. 1, 102) reaches the target value.

[0071]

[0078] Adjusting at least one antenna (FIG. 1, 104) towards the average power rather than the target power reduces the number and length of the activation sequences and stabilizes the power output of the antenna array (FIG. 1, 102). This may be done by the antenna system (FIG. 1, 100) described in FIGS. 1 - 4.

[0072]

[0079] Next, during the activation period, based on the determined difference, the control signal for the single transmitter (FIG. 1, 108) is adjusted (block 502) so that the output of at least one antenna (FIG. 1, 104) becomes the same as the average value regardless of the load on the antenna (FIG. 1, 104). This process can be repeated until the output of all antennas matches the average power output, which may match the target value when stabilized.

[0073]

[0080] As described above, in some examples, at least one antenna (FIG. 1, 104) that adjusts a control signal may be an antenna (FIG. 1, 104) within an array (FIG. 1, 102) having a maximum difference. In this example, the activation period for adjusting the control signal for this maximum offset antenna (FIG. 1, 104) is the only activation period of the activation sequence having the adjusted control signal. During subsequent activation sequences, different activation periods may include adjustment signals. Next, at least one antenna (FIG. 1, 104) is driven by a single transmitter (FIG. 1, 108) based on an adjustment control signal (block 503). That is, the adjustment control signal is passed to a power amplifier (FIG. 3, 316) to adjust the output power of the RF treatment supplied to the antenna.

[0074]

[0081] FIG. 6 shows an example of a switching device (110) that controls the selection, power, and phase of an antenna (FIG. 1, 104) according to an example of the principles described herein. In this example, the switching device (110) switches a plurality of antennas (FIG. 1, 104) on simultaneously, adjusts the power between the antennas (FIG. 1, 104) switched on simultaneously, and adjusts the phase between the antennas (FIG. 1, 104) switched on simultaneously. In this drawing, although one input and eight outputs are shown, the implementation form can be scaled up or down to any number of outputs. Further, in some cases, the switching device (110) may include a subset of the illustrated elements. For example, the switching device (110) may include a phase shift network instead of a component that adjusts the power level.

[0075]

[0082] The front end of the switching device (110) includes a single input that is distributed in parallel to eight switches (650-1, 650-2, 650-3, 650-4, 650-5, 650-6, 650-7, 650-8). Each of these switches (650) may be mechanical, electromechanical, or electrical. By connecting the switches (650) in parallel, RF power is distributed relatively evenly across the outputs of the switches (650). For example, if two switches (650) are active, the output power level at the output of each switch (650) is approximately half of the input power to the switching device (110) due to the power being split and the losses incurred from the switches (650) themselves. Thus, when power is distributed among multiple antennas (FIG. 1, 104), it may be necessary to adjust the input power to the switching device (110) to offset the fact that less power is entering each antenna (FIG. 1, 104). Due to impedance variations of multiple active switches (650), a static or dynamic impedance matcher (652) may be used to keep the load on the device driving this bank constant.

[0076]

[0083] After turning on the switches (650), each path is a variable attenuator (654-1, 654-2, 654-3, 654-4, 654-5, 654-6, 654-7, 654-8) that adjusts the output power on each branch. In some examples, since increasing the adjustment requires an active gain circuit, the power adjustment is only a decrease and there is no increase. The power decrease adjustment using the variable attenuator (654) is limited because a large power decrease generates a large amount of heat that may not be tolerated by the circuitry of the switching device (110). However, using the architecture shown in FIG. 6, the total power to the switching device (110) can be increased, selective antenna paths can be set, the power on those paths can be decreased, and the relative output power between the antennas (FIG. 1, 104) can be controlled.

[0077]

[0084] After turning on the attenuator (654), each path is a phase shifter (656-1, 656-2, 656-3, 656-4, 656-5, 656-6, 656-7, 656-8) that can shift the phase on a specific path according to a control signal. Shifting the relative phase between the antennas (Figure 1, 104) enables beamforming or steering of the radiated signal.

[0078]

[0085] Figure 7 is a flowchart of a method (700) for controlling an antenna system (Figure 1, 100) according to another example of the principles described herein. When a user or medical professional indicates that treatment should begin, the method (700) starts. This indication should occur after the head unit is worn by the patient and the TEMT device is prepared. At the start of treatment, before treatment begins, a control voltage is set to a target value (block 701). Default offsets for the individual antennas are loaded into an offset memory storage device (Figure 4, 448) (block 702), and an antenna counter is set to a first set of antennas (block 703).

[0079]

[0086] In this example, until treatment is complete, each set of antennas (Figure 1, 104) is cycled through sequentially. If multiple antennas (Figure 1, 104) are being simultaneously activated for focused treatment within the brain, the flowchart is the same. However, "N" means a group of active antennas (Figure 1, 104), not a single antenna (Figure 1, 104). In one example, at the end of each sequence, when the entire sequence is complete, only one antenna offset is updated. In other examples, multiple antenna offsets may be updated each time the sequence is complete. In some examples, the entire treatment session may be one hour, and the activation sequence may be completed in 4.6 mS (corresponding to an antenna repetition rate of 217 Hz). This results in 781,200 sequences (and opportunities for offset adjustment) occurring during the treatment session.

[0080]

[0087] Since the enablement sequence is cycled, the flow starts from the first antenna (FIG. 1, 104), or a group of antennas (FIG. 1, 104) in the array (FIG. 1, 102). First, the switching device (FIG. 1, 110) is set for that antenna (FIG. 1, 104), or group N of antennas (FIG. 1, 104) (block 704). In the case of a group of antennas (FIG. 1, 104), attenuation and phase are further set in the switching device (FIG. 1, 110) (block 705). Next, an offset for antenna set N is read from the offset memory storage device (FIG. 4, 448), and this offset is used to set the output power of the variable gain amplifier (FIG. 3, 326) (block 706). At this point, the gain path is set up, and as a result, the controller (FIG. 1, 112) enables the transmitter (FIG. 1, 108) (block 707) and generates an RF pulse for an appropriate duration.

[0081]

[0088] Before completing the RF pulse, the controller (FIG. 1, 112) reads the detected power from the coupler (FIG. 3, 328) (block 708) and amplifies what is supplied to the power detection ADC (FIG. 4, 444). If there is any factory calibration for antenna set N due to any different path loss compared to other antennas (FIG. 1, 104), the calibration offset is adjusted (block 709). Next, the read value is locally stored by the controller (FIG. 1, 112) (block 710), and as a result, the average of all antennas (FIG. 1, 104) in the sequence is calculated and the read value can be used in the power control algorithm.

[0082]

[0089] At this point, a check is made (block 711) to see if this is the last antenna (Figure 1, 104) in the activation sequence. If it is not the last antenna (Figure 1, 104) in the activation sequence (block 711, decision no), the antenna counter is incremented (block 712) and the next antenna sequence is processed. If it was the last antenna in the activation sequence (block 711, decision yes), a check is made (block 713) to see if the treatment session is complete. If the treatment session is not complete (block 713, decision no), the controller (Figure 1, 112) calculates the average detected power across the antenna (Figure 1, 104) using the stored power readings of all the antennas (block 714). Next, the controller (Figure 1, 112) compares the individual antenna readings to the average and determines which antenna (Figure 1, 104) has the power reading that is farthest from the average (block 715). This antenna, called antenna or antenna group M, is adjusted in this activation sequence. If the power reading for antenna set M is greater than the average (block 716, decision yes), the power of the variable gain amplifier (Figure 3, 326) should be decreased the next time antenna set M is active, and thus the offset is decreased by a small value (block 718) and stored in the offset memory storage location (Figure 4, 448) for antenna set M (block 718). The offset adjustment is small. That is, this change in power level changes the average power of all the antennas (Figure 1, 104) and adjusts the first power control loop in the system. Therefore, small changes should be made for system stability. If the power reading for antenna set M is less than the average (block 716, decision no), the offset value for antenna set M is increased and stored by a small amount (block 717). As described above, in some examples, method (700) includes one adjustment per activation sequence, but in the case where the maximum deviation from the average exceeds a threshold, alternative examples may simply make the adjustment. At this point, the antenna counter is reset to the first antenna (block 703) and the activation sequence is repeated.At the end of the activation sequence, if it is determined that the treatment is complete (block 713, determination yes), turn off the power of the amplifier and end the treatment.

[0083]

[0090] FIG. 8 shows an electromagnetic therapy device having an antenna system (FIG. 1, 100) according to an example of the principles described herein. The electromagnetic therapy device includes a head unit (858) that holds an antenna at a predetermined position relative to the head of a human subject. The head unit (858) further includes an array of antennas (FIG. 1, 102). As described above, each antenna (104) emits an electromagnetic wave, and a different load than the other antennas (104) in the array (FIG. 1, 102) is applied to each antenna (104). Note that FIG. 8 shows the antenna (104) on one side of the head portion. The opposite side of the head portion may include similarly positioned antennas (104).

[0084]

[0091] The electromagnetic therapy device further includes a control system (FIG. 1, 106) as shown in FIG. 1. That is, the control system (FIG. 1, 106) includes a single transmitter (FIG. 1, 108) that drives the antenna set (104), and a switching device (FIG. 1, 110) that selects a set of antennas (FIG. 1, 104) to be driven for each activation period in the activation sequence. The control system (FIG. 1, 106) further includes a controller (FIG. 1, 112) that determines the actual power output for each antenna (FIG. 1, 104) and generates an adjustment control signal for the single transmitter (FIG. 1, 108) such that the output of at least one antenna (FIG. 1, 104) is the same as a first adjusted power value regardless of the load on the antenna (FIG. 1, 104).

[0085]

[0092] For purposes of exemplifying and explaining the subject matter presented herein, the above description is merely presented. It is not intended to be exhaustive or to limit the subject matter to any precise form of disclosure. Many modifications and variations are possible in light of the above teachings.

[0086]

[0093] To best explain the principles and practical application of the subject matter, the examples described herein are selected and explained. The foregoing description is intended to enable one of ordinary skill in the art to best utilize the subject matter in various embodiments and with various modifications as are suited to the particular applications contemplated.

Claims

1. an array of antennas, each of which emits electromagnetic waves, each antenna being loaded differently than other antennas in the array; 1. A control system comprising: a single transmitter for sequentially driving the set of antennas; a switching device for selecting a set of antennas to be activated for each activation period in the activation sequence; Determine the actual power output of each antenna; generating an adjustment control signal for the single transmitter such that the power output of each antenna is controlled to match a target power for that antenna regardless of the load on that antenna; Controller and A control system including An antenna system including:

2. The antenna set includes: a single antenna active at a given time; a plurality of antennas active at a given time, the drive signal from the single transmitter being divided among the plurality of antennas; 10. The antenna system of claim 1, comprising at least one of:

3. 10. The antenna system of claim 1, wherein multiple antennas in the array focus beams in a particular direction within a target.

4. 2. The antenna system of claim 1, wherein the controller determines the actual power output of each antenna in sequence and generates an adjustment control signal for the single transmitter for each enabling sequence until at least one antenna in the array has a power output that matches the average power output across the entire set of antennas, regardless of the load on the antenna.

5. 10. The antenna system of claim 1, wherein the controller generates an adjustment control signal during switching between enablement periods.

6. 10. The antenna system of claim 1, wherein the controller changes a phase of at least one antenna output in a valid set to steer a beam.

7. 2. The antenna system of claim 1, wherein the controller varies the power of at least one antenna output in an active set to control the relative power between each set of antennas.

8. 2. The antenna system of claim 1, wherein the controller attenuates the adjustment control signal to ensure that sequential adjustments do not overshoot.

9. The switching device comprises: a variable attenuator for each antenna coupled to each switch; a phase shifter for each antenna coupled to a respective variable attenuator; Impedance matching box 10. The antenna system of claim 1, comprising at least one of:

10. The control system includes: A charging device; The internal battery and Control Panel and The antenna system of claim 1 further comprising at least one of:

11. a power control system disposed in at least one of the transmitter and the controller; The transmitter includes: An oscillator; A variable gain amplifier (VGA); A power amplifier; Coupler and Including, The controller includes: A control voltage generator; (VGA) control signal generator; 10. The antenna system of claim 1, comprising:

12. 12. The antenna system of claim 11, wherein the VGA control signal generator comprises a fixed value control signal generator.

13. The controller includes: A voltage detector; An offset memory storage device; Including, 12. The antenna system of claim 11, wherein the VGA control signal generator is for generating a VGA control signal based on a detected voltage and an offset.

14. determining, for each antenna in the array of antennas, a difference between an actual power output for each antenna and an average power output for the entire set of antennas; adjusting a control signal for a single transmitter coupled to each antenna in the array such that the power output of each antenna is controlled to match a target power for that antenna regardless of the load on that antenna; driving the at least one antenna via the single transmitter based on a first adjustment control signal; The method includes:

15. the at least one antenna being an antenna in the array of antennas having a maximum offset; The method of claim 14 , wherein the enable period for adjusting the control signal is the only enable period in an enable sequence having an adjusted control signal.

16. The method of claim 14 further comprising detecting a faulty antenna based on the offset.

17. 15. The method of claim 14, further comprising adjusting a phase of the output for each antenna in the set of antennas to focus electromagnetic waves to a specific location on a target.

18. a head unit for holding antennas in predetermined positions relative to the head, the head unit including an array of antennas each emitting electromagnetic waves, each antenna being loaded differently than other antennas in the array; 1. A control system comprising: a single transmitter driving a set of antennas; a switching device for selecting a set of antennas to be activated for each activation period in the activation sequence; Determining the power output of each antenna; generating an adjustment control signal for the single transmitter such that the power output of at least one antenna is controlled to match a target power for that antenna regardless of loading on that antenna; Controller and A control system including Electromagnetic therapy devices including:

19. 20. The electromagnetic treatment device of claim 18, further comprising an AC-DC adapter for charging the control system.

20. 20. The electromagnetic treatment device of claim 18 for the treatment or prevention of neurodegenerative diseases and conditions, and for the enhancement of non-deteriorating cognitive function.

21. a head unit for holding antennas in predetermined positions relative to the head, the head unit including an array of antennas each emitting electromagnetic waves; 1. A control system comprising: a single transmitter driving a set of antennas; a switching device for selecting a set of antennas to be activated for each activation period in the activation sequence; a controller for adjusting the phase of the output for each antenna in the set of antennas to focus the electromagnetic waves to a specific location on a target; A control system including Electromagnetic therapy devices including:

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