WO2016027119A1 - Satellite multiband antenna unit - Google Patents

Satellite multiband antenna unit Download PDF

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Publication number
WO2016027119A1
WO2016027119A1 PCT/IB2014/001845 IB2014001845W WO2016027119A1 WO 2016027119 A1 WO2016027119 A1 WO 2016027119A1 IB 2014001845 W IB2014001845 W IB 2014001845W WO 2016027119 A1 WO2016027119 A1 WO 2016027119A1
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WO
WIPO (PCT)
Prior art keywords
band
frequency
feed
antenna unit
plate
Prior art date
Application number
PCT/IB2014/001845
Other languages
French (fr)
Inventor
Thomas Lohrey
Klaus Breitsameter
Georg Emanuel August STRAUSS
Original Assignee
Eutelsat S A
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Eutelsat S A filed Critical Eutelsat S A
Priority to RU2017108746A priority Critical patent/RU2659303C1/en
Priority to EP14830538.6A priority patent/EP3183775A1/en
Priority to PCT/IB2014/001845 priority patent/WO2016027119A1/en
Publication of WO2016027119A1 publication Critical patent/WO2016027119A1/en

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Classifications

    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01Q—ANTENNAS, i.e. RADIO AERIALS
    • H01Q19/00—Combinations of primary active antenna elements and units with secondary devices, e.g. with quasi-optical devices, for giving the antenna a desired directional characteristic
    • H01Q19/10—Combinations of primary active antenna elements and units with secondary devices, e.g. with quasi-optical devices, for giving the antenna a desired directional characteristic using reflecting surfaces
    • H01Q19/12—Combinations of primary active antenna elements and units with secondary devices, e.g. with quasi-optical devices, for giving the antenna a desired directional characteristic using reflecting surfaces wherein the surfaces are concave
    • H01Q19/13—Combinations of primary active antenna elements and units with secondary devices, e.g. with quasi-optical devices, for giving the antenna a desired directional characteristic using reflecting surfaces wherein the surfaces are concave the primary radiating source being a single radiating element, e.g. a dipole, a slot, a waveguide termination
    • H01Q19/132—Horn reflector antennas; Off-set feeding
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01Q—ANTENNAS, i.e. RADIO AERIALS
    • H01Q15/00—Devices for reflection, refraction, diffraction or polarisation of waves radiated from an antenna, e.g. quasi-optical devices
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01Q—ANTENNAS, i.e. RADIO AERIALS
    • H01Q15/00—Devices for reflection, refraction, diffraction or polarisation of waves radiated from an antenna, e.g. quasi-optical devices
    • H01Q15/0006—Devices acting selectively as reflecting surface, as diffracting or as refracting device, e.g. frequency filtering or angular spatial filtering devices
    • H01Q15/0013—Devices acting selectively as reflecting surface, as diffracting or as refracting device, e.g. frequency filtering or angular spatial filtering devices said selective devices working as frequency-selective reflecting surfaces, e.g. FSS, dichroic plates, surfaces being partly transmissive and reflective
    • H01Q15/0026—Devices acting selectively as reflecting surface, as diffracting or as refracting device, e.g. frequency filtering or angular spatial filtering devices said selective devices working as frequency-selective reflecting surfaces, e.g. FSS, dichroic plates, surfaces being partly transmissive and reflective said selective devices having a stacked geometry or having multiple layers
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01Q—ANTENNAS, i.e. RADIO AERIALS
    • H01Q15/00—Devices for reflection, refraction, diffraction or polarisation of waves radiated from an antenna, e.g. quasi-optical devices
    • H01Q15/0006—Devices acting selectively as reflecting surface, as diffracting or as refracting device, e.g. frequency filtering or angular spatial filtering devices
    • H01Q15/0013—Devices acting selectively as reflecting surface, as diffracting or as refracting device, e.g. frequency filtering or angular spatial filtering devices said selective devices working as frequency-selective reflecting surfaces, e.g. FSS, dichroic plates, surfaces being partly transmissive and reflective
    • H01Q15/0033—Devices acting selectively as reflecting surface, as diffracting or as refracting device, e.g. frequency filtering or angular spatial filtering devices said selective devices working as frequency-selective reflecting surfaces, e.g. FSS, dichroic plates, surfaces being partly transmissive and reflective used for beam splitting or combining, e.g. acting as a quasi-optical multiplexer
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01Q—ANTENNAS, i.e. RADIO AERIALS
    • H01Q19/00—Combinations of primary active antenna elements and units with secondary devices, e.g. with quasi-optical devices, for giving the antenna a desired directional characteristic
    • H01Q19/10—Combinations of primary active antenna elements and units with secondary devices, e.g. with quasi-optical devices, for giving the antenna a desired directional characteristic using reflecting surfaces
    • H01Q19/12—Combinations of primary active antenna elements and units with secondary devices, e.g. with quasi-optical devices, for giving the antenna a desired directional characteristic using reflecting surfaces wherein the surfaces are concave
    • H01Q19/17—Combinations of primary active antenna elements and units with secondary devices, e.g. with quasi-optical devices, for giving the antenna a desired directional characteristic using reflecting surfaces wherein the surfaces are concave the primary radiating source comprising two or more radiating elements
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01Q—ANTENNAS, i.e. RADIO AERIALS
    • H01Q19/00—Combinations of primary active antenna elements and units with secondary devices, e.g. with quasi-optical devices, for giving the antenna a desired directional characteristic
    • H01Q19/10—Combinations of primary active antenna elements and units with secondary devices, e.g. with quasi-optical devices, for giving the antenna a desired directional characteristic using reflecting surfaces
    • H01Q19/18—Combinations of primary active antenna elements and units with secondary devices, e.g. with quasi-optical devices, for giving the antenna a desired directional characteristic using reflecting surfaces having two or more spaced reflecting surfaces
    • H01Q19/19—Combinations of primary active antenna elements and units with secondary devices, e.g. with quasi-optical devices, for giving the antenna a desired directional characteristic using reflecting surfaces having two or more spaced reflecting surfaces comprising one main concave reflecting surface associated with an auxiliary reflecting surface
    • H01Q19/192—Combinations of primary active antenna elements and units with secondary devices, e.g. with quasi-optical devices, for giving the antenna a desired directional characteristic using reflecting surfaces having two or more spaced reflecting surfaces comprising one main concave reflecting surface associated with an auxiliary reflecting surface with dual offset reflectors
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01Q—ANTENNAS, i.e. RADIO AERIALS
    • H01Q5/00—Arrangements for simultaneous operation of antennas on two or more different wavebands, e.g. dual-band or multi-band arrangements
    • H01Q5/40—Imbricated or interleaved structures; Combined or electromagnetically coupled arrangements, e.g. comprising two or more non-connected fed radiating elements
    • H01Q5/45—Imbricated or interleaved structures; Combined or electromagnetically coupled arrangements, e.g. comprising two or more non-connected fed radiating elements using two or more feeds in association with a common reflecting, diffracting or refracting device

Definitions

  • the invention relates to the field of satellite communications and antennas for satellite ground terminals and is more specifically directed to multi-band antenna dish.
  • Antennas with large antenna gain with simultaneously low ground noise are of great importance for exchanging information by means of electromagnetic signals in free space. This applies in particular, if the signals is to be received are weak or the distance between the transmitter and receiver is large, such as e.g. in the case of communication involving satellites.
  • LNB Low Noise Block
  • Satellite Internet access is currently available and has found favorable market acceptance.
  • the signals are exchanged between the terrestrial antenna and the satellite bidirectionally.
  • frequencies in the Ka band typically between 26.6 and 40 GHz (uplink)
  • K band typically between 18 and 26.5 GHz (downlink), which do not overlap with the frequencies mentioned for television (Ku band) may be for instance used.
  • a known solution to this problem is to provide a single dish antenna capable of handling the two way Internet connection as well as the reception of the Ku-band satellite.
  • Such a solution is disclosed in the document US6512485 which discloses a satellite multi-band antenna comprising:
  • FSS sub-reflector - a frequency selective reflective surface (FSS) sub-reflector; - a first feed connected to a first LNB, said first feed being located in a first location for receiving signals at Ku band reflected from the main reflector and transmitted through the FSS sub- reflector;
  • FSS frequency selective reflective surface
  • the FSS sub-reflector according to US6512485 consists of a sheet of dielectric material on which is arranged a spaced array of resonant elements.
  • the resonant elements are sized and configured to resonate at the frequencies to be reflected by the FSS.
  • a FSS built with resonant elements is typically used, if a low pass be- havior of the FSS is desired.
  • the transmission losses of a FSS built with resonant elements and used as a high pass would be much too high.
  • Document EP0059343 discloses a multi-band antenna comprising a frequency-selective reflecting surface (FSRS) of high-pass type.
  • the FSRS comprises two or three metallic square-apertured lattices arranged in parallel to one another. Interactions between the lattices create resonance points that broaden the band pass characteristic of the FSRS.
  • the FSRS of document EP0059343 may have unpredictable effects on the antenna characteristics and the link budget over the satellite. Especially, with such resonance structure, it may be difficult to maintain the antenna characteristics in line with the specifications of the satellite operator's requirements. This concerns mainly the antenna side-lobe patterns for transmitting antennas and the cross-polar discrimination.
  • This FSRS may be sufficiently good for receiving-only solutions from high power satellite that provide sufficient link margin to compensate the attenuation of the frequency selective surface, but not for receiving and transmitting solutions in antennas with a limited transmit power.
  • One object of the present invention is to provide a satellite multi-band antenna unit for providing two-way broadband Internet access and direct broadcast television, said antenna unit using a FSS unit of high-pass type that is easier to manufacture and that has improved characteristics, especially in terms of frequency selectivity.
  • the present invention provides a satellite multi-band antenna unit comprising:
  • a first feed connected to a first low noise down converter, said first feed being located in a first location for receiving radiation in a first frequency band, said radiation in the first frequency band comprising a plurality of incident beams reflected from said main reflector and transmitted through said frequency selective reflective unit;
  • a second feed connected to a second low noise down converter, said second feed being located in a second location for receiving radiation in a second frequency band lower than said first frequency band, said radiation in the second frequency band comprising a plurality of incident beams reflected from said main reflector and from said frequency selective unit;
  • said frequency selective reflective unit comprises at least two electrically conductive plates facing each other, each plate having an array of spaced apart apertures, and wherein the spaced apart apertures of each plate have inner dimensions increasing with an angle of the incident beams, said angle of the incident beams being measured with respect to a normal vector of the frequency selective reflective unit.
  • the invention is focused on an antenna unit comprising a frequency selective reflective unit having a high pass behavior.
  • each aperture of the electrically conductive plates can be understood as a waveguide, i.e. a hollow conducting tube with uniform cross section of arbitrary shape, and not as a resonance structure.
  • the satellite multi-band antenna according to the invention may also present one or more of the features below, considered individually or according to all technically possible combinations:
  • said first frequency band covers K-band and/or Ka-band; advantageously, said first frequency band is K-band;
  • said dielectric material has permittivity substantially equal to one
  • the unit according to the invention comprises more than two plates arranged in cascade, each successive plate facing each other;
  • the ratio between the thickness of said plate and the width of the aperture is equal or smaller than 1 :4 (The ratio of a working example is 1 :4).
  • FIG. 1 shows schematically a satellite multi-band antenna unit 1 according to the invention
  • FIG. 2 to 4 illustrate schematically the frequency-dependent behavior of transmission and reflection of the frequency selective reflective unit included in the antenna unit of figure 1 ;
  • FIG. 5 and 6 show respectively the plan view and the side view of a thin plate used in cascade in a first embodiment of the antenna unit according to the invention
  • FIG. 7 illustrates the electrical equivalent circuit of the thin plate of figures 5 and 6
  • FIG. 8 and 9 illustrate the frequency-dependent behavior of the reflection and the transmission factors (in dB) as a function of frequency for two different sizes of the apertures of the thin plate of figures 5 and 6 ;
  • FIG. 10 illustrates schematically the frequency selective reflective unit included in the antenna unit of the first embodiment
  • FIG. 13 and 14 illustrate the frequency-dependent behavior of the reflection and the transmission factors (in dB) as a function of frequency for the frequency selective reflective unit of figure 10;
  • FIG. 16 shows the plan view of a thin plate used in cascade in a second embodiment of the antenna unit according to the invention.
  • Figure 1 shows schematically a satellite multi-band antenna unit 1 according to the invention.
  • Said satellite multi-band antenna unit 1 comprises:
  • FSR frequency selective reflective
  • a first feed 4 mounted to a transceiver 5 in a housing including both a first low noise down converter (LNB) and a transmitter acting as an up-converter ;
  • LNB low noise down converter
  • the main reflector 2 is for instance a parabolic reflector dish which in front fed offset parabolic reflector with a prime focus 8 on the forward concave side 9 of the dish.
  • the rear convex side 10 of dish 2 is for instance bolted to a non-represented rear support bracket supporting on a nonrepresented mounting mast.
  • the FSR 3 is tilted of an angle a compared to the symmetry axis AA' of the parabolic shape of the main reflector 2.
  • a typical value of this angle a is 70°; said angle a is preferably less than or equal to 90°.
  • the first feed 4 makes it possible to handle Internet communication bi-directionally and is substantially placed at the prime focus 8 (i.e. in or in the vicinity of the focal point of the parabolic reflector).
  • the transceiver 5 includes:
  • a first LNB which receives from said first feed 4 downlink signals that may be in the K-band (18-26.5 GHz), amplifies the received signals with as little noise as possible and converts the same to lower frequencies for providing to an indoor data modem ;
  • an up-converter which receives signals from the data modem and converts the same to higher frequencies that may be for instance in the Ka-band (26.6-40 GHz) for providing uplink signals to said first feed 4.
  • the FSR unit 3 is positioned for, when acting as a reflector, defining an image focus 1 1 of the main reflector 2.
  • the structure of the FSR unit 3 according to the invention will be detailed later with respect to figures 10 and 16.
  • the second feed 6 makes it possible to handle Television signals and is substantially placed at the image focus 1 1 (i.e. in or in the vicinity of the image focal point of the main parabolic reflector 2).
  • the second LNB 7 receives from said second feed 6 downlink signals that may be in the Ku-band (10.7-12.75 GHz), amplifies the received signals with as little noise as possible and converts the same to lower frequencies for providing TV signals.
  • frequencies in the Ka band (uplink) and K band (downlink) do not overlap with the frequencies mentioned in the Ku band for television.
  • the FSR unit 3 is placed in the beam path between the feeds (i.e. respectively said first and second feeds 4 and 6) and the main reflector 2.
  • the FSR unit 3 is designed to operate differently depending on the signal frequency; in other words, signals are either transmitted through the FSR unit 3 or reflected by said FSR unit. In this case, it is desired that for a certain frequency the reflection is either very large and the transmission is very small or the transmission is very large and the reflection of the signals is very small.
  • FIGs 2 to 4 show schematically the frequency-dependent behavior of transmission and reflection of the FSR unit 3 included in the antenna unit of figure 1 for various frequencies.
  • the FSR unit 3 is designed and configured to be substantially transparent to a first radiation field 20 in the Ka or K bands (Fig.2) while reflecting a second radiation field 21 in the Ku band (Fig.3). Both radiation fields 20 and 21 may be superposed (Fig.4), resulting in a multi-band communication antenna (typically, Ku-band is dedicated to television and K- /Ka-band is dedicated to Internet access).
  • the frequency-dependent behavior of FSR unit 3 corresponds to a high-pass filter: high-frequency signals corresponding to the first radiation field 20 (i.e. for instance higher than 19.5 GHz) are transmitted while low-frequency signals corresponding to the second radiation field 21 (i.e. for instance lower than 12.75 GHz) are reflected by the FSR unit 3.
  • Each of these electromagnetic waves 20 and 21 may be represented by a plurality of beams. Because of the finite distance between the main reflector 2 and the FSR unit 3 (Fig.1 ) (or between the feeds 4, 6 and the FSR unit 3 if transmission of satellite signals is considered), each beam incidences with a different angle on the FSR unit 3. It is thus considered that the in- cident beams are not parallel. The beams of the transmitted radiation field 20 converge on the prime focus 8, whereas the beams of the reflected radiation field 21 converge on the image focus 1 1 .
  • each beam and a direction normal to the surface of the plate 30 varies according to the position of the beam on said surface.
  • three incident beams 201 , 202 and 203 are represented: upper beam 201 is incident on FSR unit 3 with an angle ⁇ greater than the angle ⁇ 2 of middle beam 202, itself greater than the angle ⁇ 3 of lower beam 203 ( ⁇ 1 > ⁇ 2 > ⁇ 3).
  • Lower beam 203 is the clos- est beam to focal points 8 and 1 1 (prime focus 8 and image focus 1 1 face the bottom of FSR unit 3).
  • the FSR unit 3 comprises a plurality (here two) of frequency selective thin plates and (such as the thin plate 30 repre- sented in the figures 5 and 6 or the thin plate 30' represented in the figure 16) as a cascade in a given defined spacing. Benefits of using two or more plates in cascade will now be explained, in relation to figures 5 to 14.
  • the figures 5 and 6 shows respectively the plan view and the side view of a thin plate 30 that may be included in the FSR unit 3 according to a first embodiment of the invention.
  • Said thin plate 30 is a single frequency selective plate with a plurality of rectangular apertures 31 .
  • the plate 30 is chosen to be square.
  • Each of the rectangular apertures 31 of the thin plate 30 is identical with edge lengths Ax and A y .
  • the arrangement is based on a square grid with a period p. Said apertures 31 are thus periodically (along both of their lengths) arranged according to a lattice structure.
  • the thickness of the plate 30 is h.
  • the plate 30 is thin which means that the inner dimensions of the apertures (either edge lengths Ax and Ay) are much larger than the thickness h.
  • the plate itself 30 is made of an electrically conductive material such as metal.
  • a material with large conductivity should be selected (for instance, cooper, silver, aluminum or brass).
  • Each of the apertures 31 may be understood as a waveguide (con- sidering the plate 30 as a two-dimensional grid with apertures having a cross-section independent of the depth) which, similarly to the case of a hollow waveguide, has a cutoff frequency fcutoff.
  • a waveguide con- sidering the plate 30 as a two-dimensional grid with apertures having a cross-section independent of the depth
  • fcutoff a cutoff frequency
  • the thin plate 30 is equivalent to an electrical two-port network, which consists of a parallel-connected coil of inductance L.
  • This equivalent circuit describes approximately the electrical behavior of the signal flow for the considered range of frequency (one has to note that the complete equivalent circuit should comprise a capacitance but the influence of such capacitance in the considered frequency range is negligible).
  • the inductance L is dependent on the extension of the waveguides perpendicular to the orientation of the electric field vector, that's it the inner dimensions Ax, A y of the apertures 31 , and on the length of the waveguide (i.e. the thickness h of the plate 30). With decreasing size (Ax and/or Ay) of the apertures 31 , the inductance L decreases and in terms of its properties approaches a short circuit. The same happens when the length h of the waveguides 31 increases. Yet, the inductance L determines the cutoff frequency of the waveguides, and consequently, transmission and reflection behavior of the plate.
  • the plates used in cascade are of the type represented in figures 5 and 6, with apertures of uniform size.
  • Such an arrangement of the FSR 3 unit is represented in figure 10.
  • the FSR unit 3 comprises:
  • said first electrically conductive plate 30A and said second electrically conductive plate 30B have the same dimension and are made of the same material; advantageously, each of the first and second plates 30A and 30B are identical to the plate 30 as shown in figures 5 and 6.
  • the plates 30A and 30B are facing each other such that an aperture of the plate 30A is face to face to a corresponding aperture of the plate 30B.
  • the distance between the plates 30A and 30B, i.e. the thickness d of the dielectric spacer 12 is substantially equal to ⁇ /4, where ⁇ is the wavelength at the cutoff frequency of the aper- tures 31 .
  • the electrically isolating spacer 12 should preferably have a relative electrical permittivity e r close to one.
  • e r relative electrical permittivity
  • materials with higher electrical permittivity can be used as well.
  • the dielectric loss angle has to be small (e.g. ⁇ 0.01 ).
  • isolating materials used for the isolating spacer 12 are Rohacell® (Evonic) or other structural foams like polystyrene.
  • Figure 1 1 shows a first equivalent circuit of the frequency selective reflective unit of figure 10.
  • Each of the single thin plates 30A and 30B is replaced by an inductance L (as discussed in relation to figure 7) while the dielectric spacer 12 is replaced by a ⁇ / 4 length transmission line.
  • a ⁇ / 4 length transmission line acts like an impedance inverter, the inverter constant of which is equal to the line characteristic impedance of the transmission line. Therefore, the transmission line with a ⁇ / 4 length and the inductor L on the right of figure 1 1 can be substituted by a capacitor C serially connected with the inductance L on the left.
  • An L-C circuit is then ob- tained, as shown in figure 12 that represents another equivalent circuit (which corresponds to a high pass filter) of the frequency selective reflective unit of figure 10.
  • the high-pass character of the circuit from figure 7 is improved by forming a cascade with the serial-connected capacitor, to make the frequency selective reflective unit of figure 10 equivalent to an L-C circuit, i.e. to a simple high-pass filter.
  • the dielectric spacer 12 should be as low loss as possible, that's why the electrical permittivity of which should be as close to one as possible.
  • the thickness d of the layer is approximately equal to ⁇ / 4, wherein ⁇ is the wavelength at the cutoff frequency fcutoff of the high-pass filter.
  • the reflection and transmission factors depends on the angle ⁇ of the beams that constitute the incident radiation field. Specifically, the transmission factor decreases when the angle ⁇ increases, whereas the reflection factor increases. Therefore, the reflection and transmission behavior of the waveguides may vary depending on their location in the plates.
  • the FSR unit 3 In a second embodiment of the FSR unit 3, it is proposed to adapt the dimensions of the waveguide in each lattice point of the plates, so that the transmission and reflection factors are the same for each beam of the inci- dent radiation field. In this way, the properties of the antenna will be preserved.
  • Such a plate 30' is schematically illustrated in figure 16.
  • the apertures 31 ' at the top of the plate 30' are made larger than the apertures 31 ' at the bottom of the plate 30'. This allows the level of the transmission factor at the top of the plate (where the incidence angle is high) and the level of the reflection factor at the bottom of the plate (where the incidence angle is low) to be raised.
  • the inner dimensions Ax, A y of the apertures 31 ' belonging to the same row of the lattice are preferably the same.
  • the angle ⁇ of the incident beams is typically comprised between 30 and 70 degrees.
  • the plates 30' are configured in the same manner as the plates 30 to form a FSR unit 3 and present the same advantages as those described in relation to figures 10 to 14.
  • this invention provides a multi-band antenna useful in any application where three radio frequency receiver or transmitter modules are operated with a single dish antenna and the three modules operate on three frequency bands and which need not be limited to the Ka and K bands and Ku-band applications described above.

Abstract

The invention relates to a satellite multi-band antenna unit comprising a main reflector; a frequency selective reflective unit; a first feed connected to a first low noise down converter, said first feed being located in a first location for receiving radiation in a first frequency band, said radiation in the first frequency band comprising a plurality of incident beams reflected from said main reflector and transmitted through said frequency selective reflective unit; a second feed connected to a second low noise down converter, said second feed being located in a second location for receiving radiation in a second frequency band lower than said first frequency band, said radiation in the second frequency band comprising a plurality of incident beams reflected from said main reflector and from said frequency selective unit; and a transmitter connected to one of said first or second feed for transmitting uplink radiation to said main reflector. Said frequency selective reflective unit comprises at least two electrically conductive plates (30') facing each other, each plate having an array of spaced apart apertures (31 '). The spaced apart apertures (31') of each plate have inner dimensions (Ax1 increasing with an angle of the incident beams.

Description

SATELLITE MULTIBAND ANTENNA UNIT
The invention relates to the field of satellite communications and antennas for satellite ground terminals and is more specifically directed to multi-band antenna dish.
Antennas with large antenna gain with simultaneously low ground noise are of great importance for exchanging information by means of electromagnetic signals in free space. This applies in particular, if the signals is to be received are weak or the distance between the transmitter and receiver is large, such as e.g. in the case of communication involving satellites.
It is well known that reflector antennae are used for the terrestrial re- ception of radio signals (satellite television), which are transmitted by means of a geostationary satellite, the surfaces of which reflector antennae correspond to a parabolic contour. The reflector antennae are fed by so-called feed antennae (often also termed feed or primary emitters). A so-called Low Noise Block (LNB) is generally integrated into the feed, which amplifies the received signals with as little noise as possible and converts the same to lower frequencies. The phase center of the feed is located in or in the vicinity of the focal point of the paraboloid. According to the current prior art, the receiving frequencies of television signals mostly lie in the Ku band, typically between 10.7 and 12.75 GHz.
Recently, access to the Internet via satellite has become increasingly important; it offers a very good option to the consumer seeking broadband Internet connectivity where no terrestrial alternatives such as cable or telephone line based broadband service are available. Satellite Internet access is currently available and has found favorable market acceptance. In this case, the signals are exchanged between the terrestrial antenna and the satellite bidirectionally. In said bi-directional systems, frequencies in the Ka band, typically between 26.6 and 40 GHz (uplink), and K band, typically between 18 and 26.5 GHz (downlink), which do not overlap with the frequencies mentioned for television (Ku band), may be for instance used.
Service proposing bidirectional high-speed access service to the internet by satellite can, however, equip a limited number of users and, more- over, requires bulky equipment which is difficult to install (heavy antenna supports, the obligation to add a second antenna or to replace the existing antenna and the passing of one or two additional coaxial cables).
A known solution to this problem is to provide a single dish antenna capable of handling the two way Internet connection as well as the reception of the Ku-band satellite. Such a solution is disclosed in the document US6512485 which discloses a satellite multi-band antenna comprising:
- a main parabolic reflector;
- a frequency selective reflective surface (FSS) sub-reflector; - a first feed connected to a first LNB, said first feed being located in a first location for receiving signals at Ku band reflected from the main reflector and transmitted through the FSS sub- reflector;
- a second feed connected to a second LNB, said second feed being located in a second location for receiving signals in Ka- band reflected from the main reflector and from the FSS sub- reflector;
- a transmitter connected to said second feed for transmitting uplink signals in Ka-band to the main reflector.
The FSS sub-reflector according to US6512485 consists of a sheet of dielectric material on which is arranged a spaced array of resonant elements. The resonant elements are sized and configured to resonate at the frequencies to be reflected by the FSS.
A FSS built with resonant elements is typically used, if a low pass be- havior of the FSS is desired. The transmission losses of a FSS built with resonant elements and used as a high pass would be much too high.
Other types of FSS are also known (see for instance the article "Performance of the X-/Ka-/KABLE-Band Dichroic Plate in the DSS-13 Beam Waveguide Antenna" - Chen et al - TDA Progress Report 42-1 15, Novem- ber 1993). In the latter case, the FSS is a single conductive plate with apertures. The disadvantage of such arrangement principally consists in the complex production so that the requirements for transmission and reflection can be fulfilled; among other things, the thickness of the plate compared to the thickness of the apertures' sidewalls, i.e. the aspect ratio, must be relatively large. As the apertures are realized in a rectangular manner, a simple production by means of drilling is not possible. In other publications, the shape of the apertures is varied (e.g. cruciform) or the cross section of the aperture is changed as a function of the depth of the aperture, which likewise requires very complex production process.
Document EP0059343 discloses a multi-band antenna comprising a frequency-selective reflecting surface (FSRS) of high-pass type. The FSRS comprises two or three metallic square-apertured lattices arranged in parallel to one another. Interactions between the lattices create resonance points that broaden the band pass characteristic of the FSRS. However, with such resonance structure, The FSRS of document EP0059343 may have unpredictable effects on the antenna characteristics and the link budget over the satellite. Especially, with such resonance structure, it may be difficult to maintain the antenna characteristics in line with the specifications of the satellite operator's requirements. This concerns mainly the antenna side-lobe patterns for transmitting antennas and the cross-polar discrimination. This FSRS may be sufficiently good for receiving-only solutions from high power satellite that provide sufficient link margin to compensate the attenuation of the frequency selective surface, but not for receiving and transmitting solutions in antennas with a limited transmit power.
One object of the present invention is to provide a satellite multi-band antenna unit for providing two-way broadband Internet access and direct broadcast television, said antenna unit using a FSS unit of high-pass type that is easier to manufacture and that has improved characteristics, especially in terms of frequency selectivity.
More precisely, the present invention provides a satellite multi-band antenna unit comprising:
- a main reflector;
- a frequency selective reflective unit;
- a first feed connected to a first low noise down converter, said first feed being located in a first location for receiving radiation in a first frequency band, said radiation in the first frequency band comprising a plurality of incident beams reflected from said main reflector and transmitted through said frequency selective reflective unit;
- a second feed connected to a second low noise down converter, said second feed being located in a second location for receiving radiation in a second frequency band lower than said first frequency band, said radiation in the second frequency band comprising a plurality of incident beams reflected from said main reflector and from said frequency selective unit;
- a transmitter connected to one of said first or second feed for transmitting uplink radiation to said main reflector; wherein said frequency selective reflective unit comprises at least two electrically conductive plates facing each other, each plate having an array of spaced apart apertures, and wherein the spaced apart apertures of each plate have inner dimensions increasing with an angle of the incident beams, said angle of the incident beams being measured with respect to a normal vector of the frequency selective reflective unit.
The invention is focused on an antenna unit comprising a frequency selective reflective unit having a high pass behavior.
According to the invention, it is proposed to use at least two electrically conductive plates as a cascade and spaced by a given distance to improve the frequency behavior of the frequency selective reflective unit. Each aperture of the electrically conductive plates can be understood as a waveguide, i.e. a hollow conducting tube with uniform cross section of arbitrary shape, and not as a resonance structure.
The fact of using a cascade of plates (in place of a single thick plate) makes it possible to use thin plates with a very small aspect ratio and that are much easier to manufacture (for instance to obtain rectangular or square apertures by means of drilling). Besides, the fact that the inner dimensions of the apertures increase when the angle of the incident beams increases allows the transmission and reflection factors to be the same for each beam of the incident radiation. The satellite multi-band antenna according to the invention may also present one or more of the features below, considered individually or according to all technically possible combinations:
- said transmitter is connected to said first feed;
- said first frequency band covers K-band and/or Ka-band; advantageously, said first frequency band is K-band;
- said second frequency band is Ku-band;
- the distance between said plates is substantially equal to λ/4 where λ is the wavelength at the waveguide cutoff frequency of said apertures;
- said plates are separated by a dielectric material;
- said dielectric material has permittivity substantially equal to one;
- said plates have the substantially same dimensions; - the unit according to the invention comprises more than two plates arranged in cascade, each successive plate facing each other;
- for each plate, the ratio between the thickness of said plate and the width of the aperture is equal or smaller than 1 :4 (The ratio of a working example is 1 :4).
Other characteristics and advantages of the invention will appear reading the following description of an embodiment of the invention, given by way of example and with reference to the accompanying drawings, in which:
- Figure 1 shows schematically a satellite multi-band antenna unit 1 according to the invention;
- Figures 2 to 4 illustrate schematically the frequency-dependent behavior of transmission and reflection of the frequency selective reflective unit included in the antenna unit of figure 1 ;
- Figures 5 and 6 show respectively the plan view and the side view of a thin plate used in cascade in a first embodiment of the antenna unit according to the invention;
- Figure 7 illustrates the electrical equivalent circuit of the thin plate of figures 5 and 6; - Figures 8 and 9 illustrate the frequency-dependent behavior of the reflection and the transmission factors (in dB) as a function of frequency for two different sizes of the apertures of the thin plate of figures 5 and 6 ;
- Figure 10 illustrates schematically the frequency selective reflective unit included in the antenna unit of the first embodiment;
- Figures 1 1 and 12 illustrate two electrical equivalent circuits of the frequency selective reflective unit of figure 10;
- Figures 13 and 14 illustrate the frequency-dependent behavior of the reflection and the transmission factors (in dB) as a function of frequency for the frequency selective reflective unit of figure 10;
- Figure 15 illustrates the amplitudes of the reflection and transmission factors, in function of the angle of the incident radiation field; and
- Figure 16 shows the plan view of a thin plate used in cascade in a second embodiment of the antenna unit according to the invention.
Figure 1 shows schematically a satellite multi-band antenna unit 1 according to the invention.
Said satellite multi-band antenna unit 1 comprises:
- a main reflector 2;
- a frequency selective reflective (FSR) unit 3;
- a first feed 4 mounted to a transceiver 5 in a housing including both a first low noise down converter (LNB) and a transmitter acting as an up-converter ;
- a second feed 6 connected to a second LNB 7.
The main reflector 2 is for instance a parabolic reflector dish which in front fed offset parabolic reflector with a prime focus 8 on the forward concave side 9 of the dish. The rear convex side 10 of dish 2 is for instance bolted to a non-represented rear support bracket supporting on a nonrepresented mounting mast. Advantageously, the FSR 3 is tilted of an angle a compared to the symmetry axis AA' of the parabolic shape of the main reflector 2. A typical value of this angle a is 70°; said angle a is preferably less than or equal to 90°.
The first feed 4 makes it possible to handle Internet communication bi-directionally and is substantially placed at the prime focus 8 (i.e. in or in the vicinity of the focal point of the parabolic reflector).
As mentioned above, the transceiver 5 includes:
- a first LNB which receives from said first feed 4 downlink signals that may be in the K-band (18-26.5 GHz), amplifies the received signals with as little noise as possible and converts the same to lower frequencies for providing to an indoor data modem ;
- an up-converter which receives signals from the data modem and converts the same to higher frequencies that may be for instance in the Ka-band (26.6-40 GHz) for providing uplink signals to said first feed 4.
The FSR unit 3 is positioned for, when acting as a reflector, defining an image focus 1 1 of the main reflector 2. The structure of the FSR unit 3 according to the invention will be detailed later with respect to figures 10 and 16.
The second feed 6 makes it possible to handle Television signals and is substantially placed at the image focus 1 1 (i.e. in or in the vicinity of the image focal point of the main parabolic reflector 2).
The second LNB 7 receives from said second feed 6 downlink signals that may be in the Ku-band (10.7-12.75 GHz), amplifies the received signals with as little noise as possible and converts the same to lower frequencies for providing TV signals.
In the present embodiment considered by way of example only, frequencies in the Ka band (uplink) and K band (downlink) do not overlap with the frequencies mentioned in the Ku band for television.
The FSR unit 3 is placed in the beam path between the feeds (i.e. respectively said first and second feeds 4 and 6) and the main reflector 2. The FSR unit 3 is designed to operate differently depending on the signal frequency; in other words, signals are either transmitted through the FSR unit 3 or reflected by said FSR unit. In this case, it is desired that for a certain frequency the reflection is either very large and the transmission is very small or the transmission is very large and the reflection of the signals is very small.
Figures 2 to 4 show schematically the frequency-dependent behavior of transmission and reflection of the FSR unit 3 included in the antenna unit of figure 1 for various frequencies. As it can be seen in those figures, the FSR unit 3 is designed and configured to be substantially transparent to a first radiation field 20 in the Ka or K bands (Fig.2) while reflecting a second radiation field 21 in the Ku band (Fig.3). Both radiation fields 20 and 21 may be superposed (Fig.4), resulting in a multi-band communication antenna (typically, Ku-band is dedicated to television and K- /Ka-band is dedicated to Internet access). Here, the frequency-dependent behavior of FSR unit 3 corresponds to a high-pass filter: high-frequency signals corresponding to the first radiation field 20 (i.e. for instance higher than 19.5 GHz) are transmitted while low-frequency signals corresponding to the second radiation field 21 (i.e. for instance lower than 12.75 GHz) are reflected by the FSR unit 3.
Each of these electromagnetic waves 20 and 21 may be represented by a plurality of beams. Because of the finite distance between the main reflector 2 and the FSR unit 3 (Fig.1 ) (or between the feeds 4, 6 and the FSR unit 3 if transmission of satellite signals is considered), each beam incidences with a different angle on the FSR unit 3. It is thus considered that the in- cident beams are not parallel. The beams of the transmitted radiation field 20 converge on the prime focus 8, whereas the beams of the reflected radiation field 21 converge on the image focus 1 1 .
Stated otherwise, the angle between each beam and a direction normal to the surface of the plate 30 varies according to the position of the beam on said surface. In the example of figure 2, three incident beams 201 , 202 and 203 are represented: upper beam 201 is incident on FSR unit 3 with an angle θι greater than the angle Θ2 of middle beam 202, itself greater than the angle Θ3 of lower beam 203 (Θ1 > Θ2 > Θ3). Lower beam 203 is the clos- est beam to focal points 8 and 1 1 (prime focus 8 and image focus 1 1 face the bottom of FSR unit 3).
According to the invention, the FSR unit 3 comprises a plurality (here two) of frequency selective thin plates and (such as the thin plate 30 repre- sented in the figures 5 and 6 or the thin plate 30' represented in the figure 16) as a cascade in a given defined spacing. Benefits of using two or more plates in cascade will now be explained, in relation to figures 5 to 14.
The figures 5 and 6 shows respectively the plan view and the side view of a thin plate 30 that may be included in the FSR unit 3 according to a first embodiment of the invention. Said thin plate 30 is a single frequency selective plate with a plurality of rectangular apertures 31 . In a non-limitative embodiment, the plate 30 is chosen to be square.
Each of the rectangular apertures 31 of the thin plate 30 is identical with edge lengths Ax and Ay. The arrangement is based on a square grid with a period p. Said apertures 31 are thus periodically (along both of their lengths) arranged according to a lattice structure. In figure 5, each of the rectangular apertures 31 is chosen to be square (i.e. Ax=Ay) but the aperture can vary in size and shape.
The thickness of the plate 30 is h. As mentioned before, the plate 30 is thin which means that the inner dimensions of the apertures (either edge lengths Ax and Ay) are much larger than the thickness h. Advantageously, the ratio between the thickness of said plate 30 and the size A (here A=Ax=Ay) of the aperture is equal or smaller than 1 :4.
By way of example only (i.e. dimensions are not limitative features), the following dimensions p = 8 mm, wx = 50 μιη and h = 50 μιη are chosen.
The plate itself 30 is made of an electrically conductive material such as metal. Advantageously, a material with large conductivity should be selected (for instance, cooper, silver, aluminum or brass).
Each of the apertures 31 may be understood as a waveguide (con- sidering the plate 30 as a two-dimensional grid with apertures having a cross-section independent of the depth) which, similarly to the case of a hollow waveguide, has a cutoff frequency fcutoff. This means that electromagnetic waves of a frequency substantially lower than fcutoff cannot pass the aper- tures and are reflected. Conversely, if the frequency of an electromagnetic wave is substantially higher than fcutoff, then the same can pass the plates virtually losslessly with a quite low reflection.
As illustrated in figure 7, the thin plate 30 is equivalent to an electrical two-port network, which consists of a parallel-connected coil of inductance L. This equivalent circuit describes approximately the electrical behavior of the signal flow for the considered range of frequency (one has to note that the complete equivalent circuit should comprise a capacitance but the influence of such capacitance in the considered frequency range is negligible).
The inductance L is dependent on the extension of the waveguides perpendicular to the orientation of the electric field vector, that's it the inner dimensions Ax, Ay of the apertures 31 , and on the length of the waveguide (i.e. the thickness h of the plate 30). With decreasing size (Ax and/or Ay) of the apertures 31 , the inductance L decreases and in terms of its properties approaches a short circuit. The same happens when the length h of the waveguides 31 increases. Yet, the inductance L determines the cutoff frequency of the waveguides, and consequently, transmission and reflection behavior of the plate.
On the basis of the equivalent circuit according to figure 7, the fre- quency-dependent behavior of the reflection and the transmission factors (in dB) for two different sizes A1 and A2>A1 (the arrow 32 indicating an increasing of the size A) of the apertures is shown in figures 8 (reflection factor as a function of frequency in GHz) and 9 (transmission factor as a function of frequency in GHz). Said transmission factor is the ratio of the power densities of the transmitted to the incident electromagnetic waves and said reflection factor is the ratio of the power densities of the reflected to the incident electromagnetic waves.
It will first be noticed that increasing the size A (A=Ax=Ay in this example) (like decreasing the thickness h) results in the reflection factor getting smaller and in the transmission factor getting higher.
Furthermore, as it can be seen in figures 8 and 9, the requirements for the reflection and transmission factors (represented by the rectangular shadings) cannot be fulfilled simultaneously, neither for the aperture of size A1 or the apertures of size A2. It is then difficult to determine the size of the aperture to get an efficient behavior (high reflection) in terms of frequency in the Ku-band but a low efficiency (high transmission) in terms of frequency in the K and Ka bands.
According to the invention, in order to fulfill simultaneously the requirements for the reflection and transmission factors, it is proposed to use at least two thin plates in cascade for the FSR unit 3. In a first embodiment of the FSR unit 3, the plates used in cascade are of the type represented in figures 5 and 6, with apertures of uniform size. Such an arrangement of the FSR 3 unit is represented in figure 10.
The FSR unit 3 comprises:
- a first electrically conductive plate 30A;
- a second electrically conductive plate 30B;
- a dielectric spacer 12 between said first electrically conductive plate 30A and said second electrically conductive plate 30B.
According to the first embodiment illustrated in figure 10, said first electrically conductive plate 30A and said second electrically conductive plate 30B have the same dimension and are made of the same material; advantageously, each of the first and second plates 30A and 30B are identical to the plate 30 as shown in figures 5 and 6. The plates 30A and 30B are facing each other such that an aperture of the plate 30A is face to face to a corresponding aperture of the plate 30B. The distance between the plates 30A and 30B, i.e. the thickness d of the dielectric spacer 12, is substantially equal to λ/4, where λ is the wavelength at the cutoff frequency of the aper- tures 31 .
It can be however assumed that plates have different dimensions and shapes.
The electrically isolating spacer 12 should preferably have a relative electrical permittivity er close to one. One has however to note that materials with higher electrical permittivity can be used as well. Advantageously, the dielectric loss angle has to be small (e.g. < 0.01 ). Examples for isolating materials used for the isolating spacer 12 are Rohacell® (Evonic) or other structural foams like polystyrene. Figure 1 1 shows a first equivalent circuit of the frequency selective reflective unit of figure 10. Each of the single thin plates 30A and 30B is replaced by an inductance L (as discussed in relation to figure 7) while the dielectric spacer 12 is replaced by a λ / 4 length transmission line.
A λ / 4 length transmission line acts like an impedance inverter, the inverter constant of which is equal to the line characteristic impedance of the transmission line. Therefore, the transmission line with a λ / 4 length and the inductor L on the right of figure 1 1 can be substituted by a capacitor C serially connected with the inductance L on the left. An L-C circuit is then ob- tained, as shown in figure 12 that represents another equivalent circuit (which corresponds to a high pass filter) of the frequency selective reflective unit of figure 10.
In other words, the high-pass character of the circuit from figure 7 is improved by forming a cascade with the serial-connected capacitor, to make the frequency selective reflective unit of figure 10 equivalent to an L-C circuit, i.e. to a simple high-pass filter.
The dielectric spacer 12 should be as low loss as possible, that's why the electrical permittivity of which should be as close to one as possible. The thickness d of the layer is approximately equal to λ / 4, wherein λ is the wavelength at the cutoff frequency fcutoff of the high-pass filter. In the present case, the cutoff frequency is 12.5 GHz, which with a permittivity er substantially equal to 1 corresponds to a wavelength of 24 mm and results in d = 6 mm.
If one would like to achieve a transmission behavior which corre- sponds to a filter of larger cycle number (> 2), more than two thin plates can be correspondingly cascaded in the manner specified above.
Thanks to the invention, it is therefore possible to use cascaded thin plates with holes or apertures that are much easier to manufacture than thick plate with holes while having a frequency behavior that is comparable. Such behavior in terms of frequency requirements is illustrated in figures 13 and 14 that represent respectively the frequency-dependent behavior of the reflection and the transmission factors (in dB) as a function of frequency (in GHz) for the frequency selective reflective unit 3 of figure 10 (see curves 40 and 41 ). It can be easily seen that the frequency requirements is now fulfilled for the FSR unit 3 with an efficient behavior (high reflection) in terms of frequency in the Ku-band and a high efficiency (high transmission) in the K and Ka bands.
A shown on figure 15, the reflection and transmission factors depends on the angle Θ of the beams that constitute the incident radiation field. Specifically, the transmission factor decreases when the angle Θ increases, whereas the reflection factor increases. Therefore, the reflection and transmission behavior of the waveguides may vary depending on their location in the plates.
In a FSR unit according to figure 10, with apertures of uniform size, the dependency of the reflection and transmission factors with the incidence angle Θ may results in depreciation of the performances of the antenna, because the transmitted/reflected radiation field is disturbed. Relevant proper- ties of the antenna unit, such as gain, cross polar discrimination and side lobe suppression, are diminished. Cross polar discrimination is the attenuation of a signal transmitted in one polarization compared to the other polarization (in order to double its capacity, a communication satellite conventionally uses two distinct polarization simultaneously at the same frequency). Side lobe suppression relates to the reduction of the interferences caused by signal leakages through the side of the directional antenna.
In a second embodiment of the FSR unit 3, it is proposed to adapt the dimensions of the waveguide in each lattice point of the plates, so that the transmission and reflection factors are the same for each beam of the inci- dent radiation field. In this way, the properties of the antenna will be preserved.
Such a plate 30' is schematically illustrated in figure 16. The apertures 31 ' at the top of the plate 30' are made larger than the apertures 31 ' at the bottom of the plate 30'. This allows the level of the transmission factor at the top of the plate (where the incidence angle is high) and the level of the reflection factor at the bottom of the plate (where the incidence angle is low) to be raised. The inner dimensions Ax, Ay of the apertures 31 ' belonging to the same row of the lattice are preferably the same. For example, in antenna unit 1 of figure 1 , the angle Θ of the incident beams is typically comprised between 30 and 70 degrees. The inner dimensions of the apertures 31 ' in the plate 30' may vary gradually from Axi = 8 mm Ayi = 7 mm to Axn = 6 mm, Ayn = 4 mm, where Axi and Ayi are the inner dimensions of the apertures 31 ' in the first row at the top of the plate 30' and Axn and Ayn are the inner dimensions of the apertures 31 ' in the last row at the bottom of the plate 30'.
Except the inner dimensions of the apertures, the plates 30' are configured in the same manner as the plates 30 to form a FSR unit 3 and present the same advantages as those described in relation to figures 10 to 14.
Naturally, the present invention is not limited to the example and embodiment described and shown, and the invention can be the subject to numerous variants that are available to the person skilled in the art.
Besides, this invention provides a multi-band antenna useful in any application where three radio frequency receiver or transmitter modules are operated with a single dish antenna and the three modules operate on three frequency bands and which need not be limited to the Ka and K bands and Ku-band applications described above.

Claims

1 . Satellite multi-band antenna unit (1 ) comprising:
a main reflector (2);
- a frequency selective reflective unit (3);
a first feed (4) connected to a first low noise down converter (5), said first feed being located in a first location for receiving radiation in a first frequency band (20), said radiation in the first frequency band (20) comprising a plurality of incident beams reflected from said main reflector (2) and transmitted through said frequency selective reflective unit (3);
a second feed (6) connected to a second low noise down converter (7), said second feed being located in a second location for receiving radiation in a second frequency band (21 ) lower than said first frequency band, said radiation in the second frequency (21 ) band comprising a plurality of incident beams reflected from said main reflector (2) and from said frequency selective unit (3);
a transmitter (5) connected to one of said first or second feed for transmitting uplink radiation to said main reflector;
wherein said frequency selective reflective unit (3) comprises at least two electrically conductive plates (30') facing each other, each plate having an array of spaced apart apertures (31 '); and
wherein the spaced apart apertures (31 ') of each plate (30') have inner dimensions (Ax, Ay) increasing with an angle (Θ) of the incident beams, said angle (Θ) of the incident beams being measured with respect to a normal vector of the frequency selective reflective unit (3).
2. Satellite multi-band antenna unit according to claim 1 , wherein said transmitter (5) is connected to said first feed (4).
3. Satellite multi-band antenna unit according to claim 1 or claim 2, wherein said first frequency band covers K-band and/or Ka-band.
4. Satellite multi-band antenna unit according to anyone of the previous claims, wherein said second frequency band is Ku-band.
5. Satellite multi-band antenna unit according to anyone of the previous claims, wherein the distance between said plates (30') is substantially equal to λ/4 where λ is the wavelength at the cutoff frequency of said apertures (31 ').
6. Satellite multi-band antenna unit according to anyone of the previous claims, wherein said plates (30') are separated by a dielectric material (12).
7. Satellite multi-band antenna unit according to the previous claim, wherein said dielectric material (12) has permittivity substantially equal to one.
8. Satellite multi-band antenna unit according to anyone of the previous claims characterized in that said plates (30') have substantially the same dimensions.
9. Satellite multi-band antenna unit according to anyone of the previous claims, comprising more than two plates (30') arranged in cascade, each successive plate facing each other.
10. Satellite multi-band antenna unit according to anyone of the previous claims, wherein, for each plate (30'), the ratio between the thickness of said plate and the width of the aperture (31 ') is equal or smaller than 1 :4.
PCT/IB2014/001845 2014-08-22 2014-08-22 Satellite multiband antenna unit WO2016027119A1 (en)

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Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN108333788A (en) * 2018-01-15 2018-07-27 上海机电工程研究所 Radio frequency and infrared beams complex method and simulator

Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0059343A1 (en) 1981-02-09 1982-09-08 Nec Corporation Antenna apparatus including frequency separator having wide band transmission or reflection characteristics
JPS61142806A (en) * 1984-12-17 1986-06-30 Nec Corp High frequency demultiplexing device
GB2328319A (en) * 1994-06-22 1999-02-17 British Aerospace A frequency selective surface
EP1120856A1 (en) * 1999-06-07 2001-08-01 Universidad Politecnica De Madrid Printed circuit technology multilayer planar reflector and method for the design thereof
US6512485B2 (en) 2001-03-12 2003-01-28 Wildblue Communications, Inc. Multi-band antenna for bundled broadband satellite internet access and DBS television service
US20140225796A1 (en) * 2013-02-08 2014-08-14 Chien-An Chen Ultra-broadband offset cassegrain dichroic antenna system for bidirectional satellite signal communication

Patent Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0059343A1 (en) 1981-02-09 1982-09-08 Nec Corporation Antenna apparatus including frequency separator having wide band transmission or reflection characteristics
US4476471A (en) * 1981-02-09 1984-10-09 Nippon Electric Co., Ltd. Antenna apparatus including frequency separator having wide band transmission or reflection characteristics
JPS61142806A (en) * 1984-12-17 1986-06-30 Nec Corp High frequency demultiplexing device
GB2328319A (en) * 1994-06-22 1999-02-17 British Aerospace A frequency selective surface
EP1120856A1 (en) * 1999-06-07 2001-08-01 Universidad Politecnica De Madrid Printed circuit technology multilayer planar reflector and method for the design thereof
US6512485B2 (en) 2001-03-12 2003-01-28 Wildblue Communications, Inc. Multi-band antenna for bundled broadband satellite internet access and DBS television service
US20140225796A1 (en) * 2013-02-08 2014-08-14 Chien-An Chen Ultra-broadband offset cassegrain dichroic antenna system for bidirectional satellite signal communication

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
CHEN ET AL.: "Performance of the X-/Ka-/KABLE-Band Dichroic Plate in the DSS-13 Beam Waveguide Antenna", TDA PROGRESS REPORT 42-115, November 1993 (1993-11-01)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN108333788A (en) * 2018-01-15 2018-07-27 上海机电工程研究所 Radio frequency and infrared beams complex method and simulator

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