Abstract:
This invention allows combining broadband GW (10 +9  Watt) peak power to achieve MV/m (10 +6  Volt/meter), and GV/m (10 +9  Volt/meter), radiated E-fields of air or vacuum breakdown across the entire electromagnetic spectrum, including optical frequencies. Use of multiple antennas and independently triggered generators allows achieving GV/m fields, while by preventing the E-field induced breakdown it provides control of power and energy content at targets. The achieved broadband MV/m E-field levels and energy density significantly exceed levels required for destruction of distant electronic targets; therefore, this invention radically improves the effectiveness of electromagnetic weapons. Furthermore, collimating multiple MV/m beams allows reaching GV/m E-fields that exceed by orders of magnitude the air or vacuum breakdown needed for broadband plasma excitation at resonance plasma frequencies in the 300 GHz range, permitting energy-efficient plasma research leading to fusion.

Description:
BACKGROUND OF THE INVENTION 
       [0001]    1. Field of the Invention 
         [0002]    The present invention enables combining broadband GW peak power to achieve MV/m and GV/m radiated electromagnetic fields of air or vacuum breakdown across the entire electromagnetic spectrum, including optical frequencies. The invention applies to broadband electromagnetic radiating systems, operating in transmitting and/or receiving modes. 
         [0003]    More particularly, the invention relates to radiating systems generating the MV/m E-field that can be used as an ultimate microwave weapon facilitating the destruction of electronic systems at distances that at 1 GHz correspond to 10&#39;s of kilometres. Furthermore, the broadband character of this invention provides the maximum coupling of electromagnetic power and energy to target and the ultimate power density assures the highest probability of target destruction. The GV/m radiating systems operating in the 300 GHz frequency range, by reaching power density exceeding breakdown i.e. ionization, allow broadband excitation at resonance plasma frequencies permitting molecular, atomic and fusion research. In the receiving mode, the radiated power from single or multiple points/transmitters is received in a collimated beam/beams and is directed simultaneously to multiple spatially-dispersed broadband antennas and receivers allowing multichannel independent time and frequency data processing. 
         [0004]    2. Description of the Related Art 
         [0005]    Use of narrowband coherent (i.e. identical frequency and phase) power combined at specific frequencies (U.S. Pat. No. 7,800,538 B2 to Crouch et al.) intended to destroy distant targets vulnerable at unknown frequencies resulted in unspecified coupling of the electromagnetic energy to the target undermining the effectiveness and usefulness of the electromagnetic weapons. These designs use multiple, narrowband, relatively low power (MW instead of GW) generators operating simultaneously at different frequencies, and low gain antennas that suffer significant beam dispersion (U.S. Pat. No. 7,126,530 B2 to Brown). These factors limit the power density and E-field that can be delivered to distant targets resulting in a low probability of target destruction. 
         [0006]    As per Reference 1, a broadband radiating system that uses a single GW generator and low-gain TEM-mode antenna illuminating a reflector has a limited weapons range since there is no possibility of adding more generators and antennas to increase the radiated E-field. 
         [0007]    An effort (U.S. Pat. No. 8,576,109 B2 to Stark et al.) to create higher E-fields, by adding to the surface of the reflector of Reference 1, non-linear semiconductor switches to increase power allows generation of E-fields limited by low withstand voltage tolerance of the semiconductor devices. Since the E-field at the antenna reflector is limited to prevent damage to the semiconductor switches, the radiated E-field intensity precludes destruction of the semiconductor devices of a distant target. 
         [0008]    Reference 1. Carl E. Baum et al., “JOLT: A Highly Directive, Very Intensive Impulse-Like Radiator”, Report of ITT Industries for US Air Force Research Lab., AFRL-DE-PS-TR-2006-1073, 2006. 
       SUMMARY OF THE INVENTION 
       [0009]    This invention, by using many separate and independently triggered generators and spatially and angularly positioned high power antennas that allow adding individual pulses and beams to deliver to the target the maximum power density limited only by the E-field of air or vacuum breakdown. Operation very close to the E-field breakdown level, optimization of each generator triggering time and selection of pulse frequency spectral content, allow achieving ultimate peak power and energy transfer to the target. Delivery of broadband frequency spectral content that induces an oscillating response at specific resonance frequencies in the target further improves the energy transfer. In response to a short pulse, with duration defined by the minimum frequency of the bandwidth, the induced resonances will prolong the effects of excitation for a period proportional to the oscillation quality factor. Since the oscillation quality factor, for example for cable coupling in electronic equipment is in the range 5 to 10, the effect of single pulse excitation can be prolonged up to 10 times, reducing the number of required excitation pulses, therefore reducing the energy requirements from generators. This invention addresses only a few applications in 1 to 500 GHz frequency range, but the power addition applies to the entire electromagnetic spectrum from GHz, including optical frequencies as it assures that the power density and therefore the E-field on target does not decrease with frequency. The power density remains almost constant, as it is proportional to the radiated power that is decreasing with frequency divided by the illumination area on target that as well is decreasing with frequency. This invention allows selecting the frequency range of operation and by means of geometrical scaling assembling systems that could be used for a variety of purposes: plasma physics leading to fusion, fusion propulsion, particle accelerators, material deposition, medical interventions at molecular and atomic levels, quantum computing, nonlinear electromagnetics, electromagnetic and particle missiles, electromagnetic weapons and in other areas relaying on high power electromagnetic interactions. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0010]      FIG. 1A  is a 3D view of “on-the-axis” Cassegrain antenna of the present invention, for the illumination of targets at long-range distances. 
           [0011]      FIG. 1B  is a 3D view and ray tracing in “on-the-axis” Cassegrain antenna of the present invention. 
           [0012]      FIG. 1C  is a 2D view of ray tracing in “on-the-axis” Cassegrain antenna of the present invention. 
           [0013]      FIG. 2A  is a 3D view of “on-the-axis” Cassegrain antenna with a Barlow lens system of the present invention, for illumination of targets at long-range distances. 
           [0014]      FIG. 2B  is a 3D view and ray tracing in “on-the-axis” Cassegrain antenna with a Barlow lens system of the present invention. 
           [0015]      FIG. 2C  is a 2D view of ray tracing in “on-the-axis” Cassegrain antenna with a Barlow lens system of the present invention. 
           [0016]      FIG. 3  is a 3D view and ray-tracing showing focusing a parallel beam coming from “on-the-axis” Cassegrain antenna of  FIG. 1  or  2 . This embodiment allows illumination of targets located at distances of few beam-diameters away from the focusing lens, assuring the smallest possible diameter of the focusing point. 
           [0017]      FIG. 4A  is a view of the concave-face broadband antenna array consisting of broadband single-polarization TEM-horns with each adjacent antenna having different polarization. 
           [0018]      FIG. 4B  is a view of the convex-face broadband antenna array consisting of broadband single-polarization TEM-horns. 
           [0019]      FIG. 4C  is a view of the flat-face broadband antenna array consisting of broadband single-polarization TEM-horns. 
           [0020]      FIG. 5A  is a cutout view of the broadband single-polarization TEM-horns. 
           [0021]      FIG. 5B  is a cutout view of the dielectric-loaded single-polarization broadband TEM-horns with coaxial and strip-line input connections. 
           [0022]      FIG. 6  is a 2D and cutout view of the broadband conical double-polarization TEM-horns with coaxial and strip-line input connections. 
           [0023]      FIG. 7  is a 2D and cutout view of the broadband conical double-polarization TEM-horns of  FIG. 6  of the present invention, with coaxial and strip-line input connections and conical enclosure bisected. 
           [0024]      FIG. 8  is a 2D view of the broadband conical double-polarization TEM-horns of  FIG. 6  or  7  of the present invention, loaded with dielectric material and having coaxial and strip-line input connections. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0025]    This invention relates to broadband electromagnetic radiating systems, operating in a transmitting and/or receiving mode in the entire electromagnetic spectrum, including optical frequencies, at power levels up to or exceeding ionization. In the transmitting mode, the present invention allows combining broadband GW peak power to achieve MV/m and GV/m radiated E-fields of air or vacuum breakdown. In the receiving mode, the radiated power from a single or multiple points/transmitters is received in a collimated beam/beams and it is directed simultaneously through multiple spatially dispersed broadband antennas and receivers allowing multichannel independent time and frequency data processing at large distances. Considering the reciprocity principle in electromagnetics, only the transmitting mode operation is described in this submission. However, it should be understood that reversing the direction of signal propagation and replacing generators with receivers allows changing between transmitting and receiving mode of operation. The overall view of  FIG. 1A , B and C, show 3D physical, 3D beams and 2D beams, of focused at infinity “on-the-axis” Cassegrain antennas  40 , for the illumination of targets at long range distances. The Cassegrain antenna  40  consists of a primary reflector  10 , a secondary reflector  11 , three support arms  12  and antenna array  13 . The antenna array  13  is assembled with  32  vertically and horizontally polarized broadband individual TEM-horns  30  described in detail in  FIG. 5A . 
         [0026]    The Cassegrain antenna  40  is converting diverging conical beams  14  and  15  coming from a focal point from each illuminating TEM-horn, after being reflected from the secondary reflector  11  and primary reflector  10 , to non-diverging beams  16  and  17  that illuminate the entire target. Considering that, the radiated power from a single illuminating antenna  30  is limited to GW range, to achieve the MV/m E-field multiple illuminating antennas need to be used. This results in beam  15  originating from antennas furthest from the reflector axis being skewed  17 , i.e. the beam  17  diverges from the main beam  16 . Therefore, to prevent beam skewing it is desired to use a reflector antenna with the largest angular amplification, i.e. largest ratio of the angle between beams  14  and  15  versus angle between beams  16  and  17 . Currently the only antenna with the largest angular amplification and no focal point in the radiating path is a Cassegrain antenna and such antenna is used in this invention. To show the effect of beam skewing,  FIG. 1B and 1C  show two beams one on the axis  14  and second the most distant from the axis  15 , coming from the antenna array  13  and directed towards the target after being reflected from the secondary  11  and primary  10  reflector. The angle between beams  14  and  15  divided by angle between beams  16  and  17  that represents the beam skew, defines the angular amplification of the Cassegrain antenna. Assuming 50% efficiency of each TEM-horn, the maximum radiated peak power delivered by the embodiment of this invention is in the TW (10 +12  watt) range in the 1 to 10 GHz band, 100&#39;s of GW in the 10 to 100 GHz band and 10&#39;s of GW in the 100 to 500 GHz band. 
         [0027]    In spite of diminishing power in function of frequency, the invention assures constant power density and therefore constant E-field on target in the entire electromagnetic spectrum including optics. The method of this invention is applicable in the frequency range above 500 GHz even if the broadband TEM-horns are replaced using different antenna concepts. Moreover, progress in high power generation and antenna technology can only improve the peak-power density delivered to targets. One skilled in the art will understand that all broadband radiating systems and antennas of this invention can also operate in the narrowband mode. Furthermore, the invention could be used as broadband and narrowband multi-beam receivers and for wireless combining and dispersing information and control without switching. 
         [0028]    In broadband high power radiating systems the power density along the path from the generator to the target that may result in breakdown of the E-field, is a restraining factor in achieving the maximum radiated E-field. In this invention, to assure uniform power density along the path from individual generators to the target the power is added in stages. The first stage consists of multiple individual antennas  30  that can either be powered by one or multiple generators. In the second stage, the conical beams from each antenna in the array  13  are added by directing them into a centre point of the secondary reflector  11 . The secondary reflector directs the diverging beams from all antennas into the primary reflector  10 . The primary reflector converts all diverging beams into a non-diverging beam directed to the target. In this submission, the simpler-to-visualize and to design on-the-axis Cassegrain antenna is used. However, one skilled in the art will understand that all embodiments of this submission include off-the-axis Cassegrain type antenna arrays. When implementing this embodiment, the effects of beam dispersion and beam skew on power density at the target are to be considered. Since only beams from antennas located on the axis of the array are not skewed, for balanced design of the Cassegrain antenna the number of antennas in the array has to be limited and/or the angular amplification of the Cassegrain antenna has to be increased. 
         [0029]    For the best performance of the Cassegrain-antenna that has angular amplification of approximately 10, the power density and the distance from the antenna to the target have to be optimized. At the maximum distance, i.e. at the end of the non-diverging beam region, the target and antenna diameter are equal D t =D a =D, and the maximum number of antennas N opt  is defined by the diameter of the primary reflector 
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         [0030]    The maximum target distance R is a function of antenna diameter D λ  expressed in wavelength λ. 
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         [0031]    In the narrowband systems operating in the 1 to 5 GHz, the maximum power is lower than 1 GW and the E-field is approximately 75 kV/m for 9 m diameter reflector antenna. For identical frequency range and reflector size, the optimally designed broadband system of this invention, consisting of Cassegrain antenna using 32-antenna array delivers at a distance of R opt =500 m, 2.5 TW power, and E-field of 3 MV/m. Therefore, in comparison to the narrowband system this invention allows reaching the 75 kV/m at a distance up to 30 times greater, while illuminating a target having diameter 30 times larger. 
         [0032]    The 9 m reflector diameter expressed in the wavelength as D λ =60 allows, when scaled in the frequency, to cover the entire microwave band up to 500 GHz and as such:
       for 10 to 50 GHz band at a distance R opt =60 m, the 1 m diameter antenna delivers 100       
 
         [0034]    GW peak power, and max. E-field of 5 MV/m, 30 J/cm 2  at 20 kHz pulse repetition frequency,
       for 100 to 500 GHz band at a distance R opt =6 m, the 10 cm diameter antenna delivers 3.2 GW peak power, and max. E-field of 9 MV/m, 80 J/cm 2  at 200 kHz pulse repetition frequency.       
 
         [0036]    For all frequency bands, from 1 to 500 GHz the E-field is close to air breakdown limit and it is approximately 30 times greater than fields currently accepted as electromagnetic threats levels required for the destruction of electronic equipment. 
         [0037]    An embodiment of “on-the-axis” Cassegrain antenna focused at infinity with a Barlow lens system is shown in  FIGS. 2A , B and C. The Barlow lens system, by increasing the approximate angular amplification of m 0 ≈10 in Cassegrain antenna allows target illumination at increased distances. The embodiment of  FIGS. 2A , B and C was formed by adding the Barlow lens system to the embodiment of  FIGS. 1A , B and C. The Barlow lens system that consists of 3 lenses  18 ,  19  and  20 , enables increased illumination range without affecting the power density and E-field. The additional elements of the Cassegrain antenna  40  are the primary reflector  10 , the secondary reflector  11 , three support arms  12  and antenna array  13 . 
         [0038]    In the Cassegrain antenna with a Barlow lens system, the on-the-axis beam  14  and the most distant from the axis  15  coming from the antenna array  13  are directed towards the target after passing through the beam collimating Barlow lens system  18 ,  19  and  20 . After being reflected from the secondary reflector  11  and primary  10 , the beams are converted to non-diverging beams  16  and  17  that illuminate the entire target. The angle between beams  14  and  15  divided by the angle between beams  16  and  17  that represents the beam skew, defines the angular amplification of the Cassegrain antenna with Barlow lens system m B  while m 0  is the angular amplification of the antenna without Barlow lens systems. Since at the maximum distance, i.e. at the end of the non-diverging beam region, the target and antenna diameter are equal D t =D a =D B , the diameter of the Cassegrain antenna primary reflector  10 , when expressed in wavelength λ corresponding to the “central” frequency of the band is equal: 
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         [0039]    The maximum number of antennas N Bopt  is defined by the diameter D Bλ  of the primary reflector  10  and so is the distance R BA opt  between the antenna and target: 
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         [0040]    The Cassegrain antenna with Barlow lens system focuses the beam at the third lens  20  into an area inversely proportional to the angular amplification, resulting in an increase of the E-field at that lens. To operate below the breakdown E-field at lens  20 , the maximum angular amplification has to be limited. 
         [0041]    An example of the effect of using the Barlow lens system follows. The Cassegrain antenna with the angular amplification increased from m 0 =10 to m b =15, increases the diameter of the main reflector  10  from D λ =60 λ to D Bλ =97 λ, and increases number of antennas from N opt =32 to N Bopt =85, resulting in an optimum target distance increase from R λopt =3333 λ to R Bλopt =8338 λ. Although the peak E-field at the target remains the same, the addition of the Barlow lens system increases significantly the range and the target illumination area therefore it improves the weapons “kill capability”. Consequently in the entire 1 to 500 GHz frequency range the Cassegrain antenna with Barlow lens system having the main reflector diameter of D Bλ =97 λ, number of antennas of N Bopt =85, and the optimum target distance of R BA opt =8338 λ assures the following:
       for 1 to 5 GHz band at a distance of R opt =1250 m, the 14.5 m main reflector diameter antenna delivers 6.8 TW peak power, max. E-field of 3 MV/m, energy density of 10 J/cm 2  at 2 kHz pulse repetition frequency,   for 10 to 50 GHz band at a distance R opt =125 m, the 1.5 m main reflector diameter antenna delivers 270 GW peak power, max. E-field of 5 MV/m, energy density of 30 J/cm 2  at 20 kHz pulse repetition frequency,   for 100 to 500 GHz at a distance R opt =12.5 m, the 15 cm main reflector diameter antenna delivers 8.5 GW peak power, max. E-field of 10 MV/m, energy density of 100 J/cm 2  at 200 kHz pulse repetition frequency.       
 
         [0045]    In the above example, use of the Barlow lens system changed the angular amplification from 10 to 15, increasing the distance to target proportionally to the square of the change in the antenna amplification factor, i.e. increasing the distance 
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         [0000]    times while the maximum E-field remains unchanged. In summary, the E-field is approximately 30 times higher than fields currently accepted as electromagnetic threats causing destruction of electronic equipment. Considering the E-field obtained using this invention and currently accepted threat level in the 1 to 5 GHz band, the electronic systems located as far as 40 km away could be destroyed. Such destruction distance is approximately 100 times greater than distance achieved using current narrowband or broadband systems. 
         [0046]    An embodiment of “on-the-axis” Cassegrain antenna focused at infinity, collimating beams at a single point  22  using focusing lens  21  is shown in  FIG. 3 . In this embodiment, in spite of presence of multiple beams, only two are shown in  FIG. 3 , one on the axis  14  and second the most distant from the axis  15 , that originate from the Cassegrain antenna with or without Barlow lens system, as shown in  FIGS. 1A and 2A  of this invention. After being reflected from the secondary  11  and primary reflector  10 , the beams  16  and  17  are directed towards the focusing lens  21  and are focused at a single point  22 . The skew angle represented by the angle between beams  16  and  17  increases the size of the focal point  22 , but the effects are too small to be visible in  FIG. 3 . 
         [0047]    Collimating parallel beams radiated by many focusing Cassegrain antennas, into a single point  22  located few beam diameters from the focusing lens  21  allows achieving GV/m E-field that constitutes an enhancement in power addition. Currently, to achieve 0.5 PW peak power required for plasma studies the US National Ignition Facility (NIF) combines 192 laser beams. In this embodiment, after collimating beams coming from 192 Cassegrain antennas having diameter of D λ =60, into a single point the following is achieved.
       In 1 to 5 GHz band, in a facility having radius of 30 m the peak power of 0.5 PW and maximum E-field of 0.7 GV/m are achieved at a focal point having diameter of 50 cm. At pulse repetition frequency of 2 kHz, the total energy density of 500 kJ/cm 2  allows deposition of required for fusion 10 +4  kJ/cm 2  in 20 sec. and reaching fusion temperature of 1.5*10 +8  K in 80 min.   In 10 to 50 GHz band, in a facility having radius of 3.5 m, peak power of 20 TW and maximum E-filed of 1.4 GV/m are achieved at a focal point having diameter of 5 cm. At pulse repetition frequency of 20 kHz, the total energy density of 2000 kJ/cm 2  allows deposition of required for fusion 10 +4  kJ/cm 2  in 5 sec. and reaching fusion temperature of 1.5*10 +8  K in 12 min.   In 100 to 500 GHz band, in the facility having radius of 35 cm, peak power level of 0.6 TW and maximum E-filed of 2.4 GV/m are achieved at a focal point having diameter of 5 mm. At pulse repetition frequency of 200 kHz, the total energy density of 6000 kJ/cm 2  allows deposition of required for fusion 10 +4  kJ/cm 2  in 1.7 sec. and reaching fusion temperature of 1.5*10  8  K in 8 sec.       
 
         [0051]    This invention instead of using plasma heating at optical frequencies excites and supports oscillation of fusion plasma in the 300 GHz range therefore assuring more efficient coupling of electromagnetic energy into the plasma. Since the E-field achieved in this embodiment exceeds 100 times the breakdown E-field in vacuum, operation in the 100 to 500 GHz band allows excitation of resonances not only at the fusion plasma frequency of 300 GHz, but also at the 280 GHz fusion plasma cyclotron frequency. Additionally, the broadband excitation that covers numerous frequencies simultaneously allows tracking the change in the resonance frequencies resulting from the changes in plasma density and temperature. Furthermore, increasing frequency of excitation by shortening the pulse duration increases the E-field resulting in larger energy deposition into plasma. Operation in the 100 to 500 GHz band, assures that the diameter of focal point is in the range of 1 to 10 mm and that the 192 Cassegrain antennas occupy volume having small 35 cm radius. Considering that, standard MRI magnets already produce 10 T magnetic fields required for fusion confinement, the entire 192 Cassegrain antenna could be placed within it. Although not shown in  FIG. 3 , to prevent possible transmission loss in the focusing lens  21 , this embodiment could be modified, by replacing the focusing lens  21  with a collimating reflector tilted in respect to the main beam coming from the Cassegrain antenna to focus the beam. 
         [0052]    The embodiment of broadband concave, convex and flat face antenna arrays as presented in FIG. 2 of the U.S. Pat. No. 6,295,032 B1 which was issued Sep. 25, 2001 under the title “Broadband horn antennas and electromagnetic field test facility”, and is assigned to the applicant of the present invention is shown in  FIGS. 4A , B and C. Considering that the application of the issued Patent was electromagnetic compatibility testing that required one polarization at a time, only individually polarized arrays were addressed in the Patent. In all embodiments of this submission, the array has to radiate E-fields containing both polarizations to assure coupling of the electromagnetic field to targets that are polarization sensitive. To permit radiation of E-field having both polarizations the embodiment of  FIGS. 4A , B and C consist of broadband single-polarization TEM-horns with each adjacent antenna having different polarization. Use of double polarization antennas of  FIGS. 6 ,  7  and  8 , assures double-polarization operation of the array. In  FIGS. 4A , B and C, the antenna  50  is vertically polarized and the antenna  51  is horizontally polarized. All vertically polarized antennas have a forward extending septum  53  and symmetrical to it an antenna enclosure extension  54 . In addition, each horizontally polarized antenna has a forward extending septum  55  and (invisible in  FIGS. 4A , B, and C), an antenna enclosure extension. To prevent coupling between antennas, the electromagnetic absorbers  52 , attenuating side lobes are installed around each antenna. 
         [0053]    Each array of  FIG. 4A , B and C consists of 32 individual antennas, however this number is flexible. Different face curvature and angular positioning of each antenna in the arrays allows diverse target illumination occurring when each broadband antenna fires pulses at different times and directs them to a particular area. Depending upon the distance and size of the target in respect to the size of the array, different curvatures of the array have to be used. As such, if the size of the target corresponds to the size of the array the flat face array is used, while convex is used for small targets and concave for large. The 32-antenna concave array of  FIG. 4A , where each antenna has a gain of approximately 20 dB allows reaching high field uniformity close to the breakdown E-field level at a distance of few antenna array diameters. One skilled in the art will understand that if higher E-fields, larger illumination area and longer duration time are required the number of antennas in the array could be increased. Furthermore, using geometrical scaling, the antenna arrays operating at different frequencies can be built. 
         [0054]      FIG. 5A  shows a cut-out view of broadband high power TEM-horn that is a copy of FIG. 2 in the U.S. Pat. No. 6,295,032 B1, which was issued Sep. 25, 2001 under the title “Broadband horn antennas and electromagnetic field test facility” and is assigned to the applicant of the present invention.  FIG. 5B  shows a cut-out view of the dielectric-loaded single-polarization high power broadband TEM-horn that is a copy of FIG. 1 in the U.S. Pat. No. 6,075,495, which was issued Jun. 13, 2000 under the title “Broadband TEM-horn antenna” assigned to the applicant of the present invention. These specific types of antennas used in the embodiments of this submission have high gain, bandwidth extending for at least one decade of frequencies, conical beam, no side lobes and high voltage capabilities. The high gain and conical beam are crucial for addition of power in the smallest possible area while the low side lobes are essential for closely spacing antennas in the array.  FIG. 5A  shows a TEM-horn antenna consisting of: horn  50 , mouth of the horn  57 , septum  53 , one of two terminating resistors 100 ohm each  56 , grounding the septum to the horn enclosure  50 , EM absorbers  52  attenuating side lobes to prevent coupling between antennas and the main beam collimating lens  58 . Use of a lens  58  increases the gain of the antenna however due to the additional weight the use of the lens is optional. In  FIG. 5B  a dielectric loaded TEM-horn antenna consisting of: horn  60 , septum  63 , counter-pose to the septum  64 , two terminating resistors 100 ohm each  56 , grounding the septum to the horn enclosure  60 , and dielectric loading  65  consisting of two slabs joined along the surface  61  is presented. Two types of antenna inputs that can be used in this invention are shown: the coaxial  69  and stripline  67 . The electromagnetic absorbers attenuating side lobes to prevent coupling between antennas are not shown. The purpose of using dielectric loading of the TEM-horn antenna is to increase the breakdown voltage between the septum  64  and the enclosure  60  and to reduce the volume of the horn antenna. Such reduction allows placing more TEM-horns in an antenna array without beam skewing, resulting in an increased output power. The total output power of the antenna array increases linearly with the increase of the dielectric constant ε r , i.e., the teflon ε r =2 loaded antenna will radiate power two time higher than if air loaded antenna having ε r =1 is used.  FIG. 6 , shows broadband, conical, double-polarization, multi-septum TEM-horn that is as the double-polarization antenna of  FIG. 3A  in the U.S. Pat. No. 6,075,495, issued Jun. 13, 2000 under the title “Broadband TEM-horn antenna” assigned to the applicant of the present invention except for four ground wedges inside the horn being removed. The removal of these wedges simplifies the assembly of vertical polarization septums  73  and  74 , horizontal polarization septums  75  and  76 , and it allows the insertion of high voltage insulating and supporting structures into the horn enclosure  70  without affecting the coupling between septums. The four  100  ohm terminating resistors  56  are connecting septums  73 ,  74 ,  75  and  76  to the horn enclosure  70 . The embodiment of  FIG. 6  shows transition  71  from four septums  73 ,  74 ,  75  and  76  that allows connecting four separate generators to the TEM-horn, resulting in increasing the output power four times. Furthermore, if a single septum antenna in the antenna array  13  of the Cassegrain antenna  40  of  FIGS. 1 and 2  is replaced with the antenna of  FIG. 6 , the radiated E-field will be increased two times. 
         [0055]    Alternatively, the four generators output power could be decreased four times to maintain the same output power as in the single septum antenna while the high voltage durability of this invention apparatus will be increased. 
         [0056]    The embodiment of broadband, conical, double-polarization, multi-septum TEM-horn, bisected to form two enclosures is shown in  FIG. 7 . The antenna is identical to antenna of  FIG. 6  however, the conical enclosure  70  in  FIG. 6  is in  FIG. 7  bisected to form two enclosures  92  and  93  separated from each other along the entire length of the antenna. This allows increasing the bandwidth by a factor of four while maintaining the power and high voltage durability seen in the embodiment of  FIG. 6 . The elements of  FIG. 7  have numbers corresponding with numbers in  FIG. 6 . 
         [0057]      FIG. 8 , shows broadband, conical, double-polarization, multi-septum TEM-horn loaded with dielectric  97  having coaxial antenna input connection  71 . It should be understood by anyone who is skilled in the art, that the embodiment of  FIG. 8  consisting of dielectric loading can be used in the antennas of  FIGS. 6 and 7 . Furthermore, if a single septum antenna in the antenna array  13  of the Cassegrain antenna  40  of  FIGS. 1 and 2  is replaced with the antenna of  FIG. 8 , the generated power will be increased eight times for the antenna filled with dielectric having dielectric constant ε r =2 instead of air ε r =1. Having such increase in power allows balancing design of the Cassegrain antenna  40  and antenna array since even if the output power is increased four times instead of eight, the high voltage durability is still increased.