Hybrid band directed energy target disruption

A technique for disrupting the operation of a target containing nonlinear electronic devices generally includes generating a high frequency signal; generating a low frequency signal; modulating the high frequency signal with the low frequency signal; and emitting the modulated high frequency signal at the target.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention pertains to directed energy systems and, more particularly, to directed energy target disruption.

2. Description of the Related Art

One interesting application of directed energy systems is target disruption. Target disruption temporarily interferes with the normal operation of the target. It is non-destructive, and non-lethal. When the target is illuminated with the directed energy, it ceases to work correctly, only to resume proper function when the illumination is removed.

Historically, target disruption has been performed using low frequency signals. Substantial experience has demonstrated that signals of frequencies at or above about 10 GHz yield unsatisfactory results. Conventional practice typically utilizes signals whose frequencies are at or below about 2 GHz. Signals in the 1 kHz-1 GHz range have been demonstrated to be particularly effective against certain target sets. However, low frequency signals still have some drawbacks. For example, they require electrically large antennas to generate effective electric fields at relatively long ranges; this limitation disqualifies these sources from many applications.

The present invention is directed to resolving, or at least reducing, one or all of the problems mentioned above.

SUMMARY OF THE INVENTION

The invention includes, in its various embodiments and aspects, a method and apparatus implementing a techniques for disrupting the operation of a target containing nonlinear electronic devices. The technique generally includes generating a high frequency signal; generating a low frequency signal; modulating the high frequency signal with the low frequency signal; and emitting the modulated high frequency signal at the target.

While the invention is susceptible to various modifications and alternative forms, the drawings illustrate specific embodiments herein described in detail by way of example. It should be understood, however, that the description herein of specific embodiments is not intended to limit the invention to the particular forms disclosed, but on the contrary, the intention is to cover all modifications, equivalents, and alternatives falling within the spirit and scope of the invention as defined by the appended claims.

DETAILED DESCRIPTION OF THE INVENTION

FIG. 1is a block diagram of a scenario100in which an apparatus105is constructed and operated in accordance with the present invention. The apparatus105includes a high frequency (“HF”) source110whose output115is modulated by a signal120output by a low frequency (“LF”) modulator125. The modulated HF signal115is amplified by an amplifier140, shown inFIG. 2, and the amplified signal135is radiated from an antenna130. In this context, “high” frequency is greater than about 10 GHz and “low” frequency is less than about 1 GHz. Terms such as “about” or “approximately” used in connection with this range are a recognition of the impact of factors such as tolerances and atmospherics on signal generation and propagation.

The HF source110may be, for example, an HP83640B RF synthesizer commercially available off the shelf from Agilent Technologies, Inc., at 5301 Stevens Creek Blvd, Santa Clara, Calif. 95051, United States, telephone: +1 (877) 424-4536, facsimile: +1 (408) 345-8474 or over the World Wide Web of the Internet at www.agilent.com. The LF modulator125may be, for example, an AGILENT 33220A function generator commercially available off the shelf from Agilent Technologies. The HF signal115is a continuous wave signal whose waveform is, in the illustrated embodiment, a sinusoidal wave. The waveform of the LF signal120is, in the illustrated embodiment, a square wave. However, the invention admits wide variation in implementation. The waveform of the LF signal120, for instance, may be a sine wave in alternative embodiments.

The pulse repetition frequency and duty cycle of the modulating LF signal are significantly contributing parameters for the effectiveness of the Hybrid Band waveform.

The preferred pulse width (PW) and pulse repetition frequency (PRF) of the LF signal120is a function of the specific non-linear device in the target145. Different device types will be disrupted by a range of LF modulations, and the particular values of PRF and PW required must be characterized for the device type, and sometimes for the specific device application. This fact also applies to traditional RF directed energy systems. No single frequency is equally effective against all targets; each directed energy system must be characterized for effectiveness against its intended targets. The parameters of LF modulation would need to be established either analytically, if an interaction model of sufficient detail exists for the targeted device, or empirically, as is commonly done with traditional RF directed energy sources.

The specific phenomenology of RF interaction with electronic devices is still under study, and traditional applications of RF directed energy express effectiveness as a Probability of Effect against a target as a function of power density (typically measured in watts per square centimeter) at the target. The same measures and approach can be used to design applications of H-Band. The effective radiated power of the system required to affect a target can be determined using traditional models and calculations. The advantages of H-Band will manifest themselves by the lower power density required at the target, and/or by the higher Effective Radiated Power (ERP) for a source of similar size and weight.

The invention also admits wide variation in the manner in which the LF modulated HF signal135is modulated. In the illustrated example, the LF modulated HF signal135is amplitude modulated by the LF signal120at a 100% depth of modulation. Other modulation techniques may be employed. Such alternative modulation techniques may include lesser depths of modulation, although at an increased power requirement. Alternative modulation techniques may also consist of different pulse repetition frequencies and duty factors.

The LF modulated, HF signal135output by the apparatus105is emitted toward a target145. As mentioned above, the LF modulated, HF signal135is emitted using antenna130. The antenna130is, in the illustrated embodiment, a pyramidal horn, which is commercially available off the shelf available from Narda Microwave at L-3 Communications Narda Microwave—West 107 Woodmere Road, Folsom, Calif. 95630, USA, telephone: 916-351-4500, facsimile: 916-351-4550, or over the World Wide Web of the Internet at http://www.nardamicrowave.com/. The invention also admits wide variation in the manner in which the HF signal124is modulated. In the illustrated example, the HF signal124is modulated by toggling the HF source110between “ON” and “OFF” states. However, other modulation techniques may be employed. Such alternative modulation techniques may include a sinusoidal modulation of the amplifier power.

The LF modulated, HF signal135output by the apparatus105is emitted toward a target1345. As mentioned above, the LF modulated, HF signal135is emitted using antenna130. Note that the LF modulated, HF signal135is conditioned in the illustrated embodiment using the circuit shown inFIG. 2.

The target145is an electronic apparatus of some kind comprised of, among other things, nonlinear electronic devices (not shown). Nonlinear electronic devices include, for example, diodes, oscillators, analog-to-digital converters, digital-to-analog converters, phase-locked-loops, transistors, operational amplifiers, and other components and circuits. Those in the art will realize that this list is illustrative only, and is not exhaustive. Nonlinear electronic devices are well known across many arts and the target145may include any nonlinear electronic device.

It is known that the efficacy of the present invention is tied to some relationship between the frequency of the modulation and the frequencies of the circuits including the nonlinear electronic devices. Thus, some degree of tuning may be desirable in some embodiments where the nature and/or composition of the target145is known or suspected a priori. However, the relationship is not well understood and the current tuning technique is the application of trial and error.

FIG. 3illustrates a method300performed in accordance with one particular aspect of the present invention. The method300may be implemented in, for example, the operation of the apparatus105inFIG. 1. The method300begins by generating (at305) a high frequency signal and generating (at310) a low frequency signal. Next, the high frequency signal is modulated (at315) by the low frequency signal. Finally, the modulated high frequency signal is emitted (at320) at the target.

FIG. 4A-FIG.4B illustrate alternative variations on the embodiment ofFIG. 1. The scenario400, shown inFIG. 4A, employs an apparatus405in which the high frequency signal115is modulated by the low frequency signal120by mixing the two signals. Mixers such as the mixer410are well known on the art and are readily commercially available off the shelf. Any suitable mixer may be employed. In the scenario401, shown inFIG. 4B, an apparatus406employs the amplifier140, better shown inFIG. 2, to combined the high and low frequency signals115,120.

The invention admits variation in implementation, such as that shown inFIG. 5. In the scenario500ofFIG. 5, the apparatus505includes two HF sources110a,110b, both of which are modulated by a common LF modulator125. The frequencies of the HF sources110a,110bare offset by a small amount, usually a value from the typical range of LF modulations. The frequency difference (offset) should be distinct and different from the LF modulator125for each implementation.

The LF modulated HF signals135a,135bare then combined by a combiner510and amplified by the amplifier140and broadcast via the antenna130. The signals135a,135bare combined by a combiner510. Combiners such as the combiner510are well known on the art and are readily commercially available off the shelf. Any suitable combiner may be employed. The amplifier140is shown inFIG. 2. The target145sees a beat frequency in the output signal135. The beat frequency of the output signal135is LF modulated, as well, and causes the effect of the invention's application on the non-linear electronics of the target145. This, in turn, disrupts the operation of the target145. This implementation would be useful in cases where the target was known or suspected to have components that were susceptible to different LF radiation frequencies.

FIG. 6A-FIG.6E illustrate a plurality of scenarios600-604that are a variations on the theme of the scenario500inFIG. 5. In the scenario600ofFIG. 6A, the modulation occurs after the combining of the frequency offset, HF signals output by the HF sources110a,110bby mixing with the LF signal120. In the scenario601ofFIG. 6B, modulation occurs after combination of the signals135a,135b.FIG. 6Cillustrate a scenario602, in which the modulated HF signals135care neither combined nor mixed. In the scenario603ofFIG. 6D, a common LF signal120is mixed with the HF signals135a,135b.FIG. 6Eillustrates a scenario604wherein modulation occurs through the amplifiers140. In each case, the resultant signals135cand135dperforms in the same manner and has the same effect on the target145as does the signal135in the scenario500ofFIG. 5. Still other variations may become apparent to those in the art having the benefit of this disclosure.

Thus, by modulating the high frequency source (e.g., greater than about 10 GHz) at a low frequency (e.g., less than about 1 GHz), low frequency effects are produced from the high frequency signal. Modifying the high frequency source of the RF energy nevertheless provides a more efficient method of energy transfer allowing transmission across greater distances and the application of lower average power levels to achieve the desired effect. The present invention also, by permitting use of higher frequency sources, also yields associated advantages in antenna size and propagation. By modulating the source at less than about 1 GHz rates, low frequency effects are produced from the high frequency signal. Consequently, the present invention propagates energy with the efficiencies of the HF signal, while disrupting the target with the effectiveness of the LF signal. The ability to design an LF modulation that is effective is constrained in the same manner as for a traditional RF directed energy system.