US3806932A - Amplitude steered array - Google Patents

Amplitude steered array Download PDF

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Publication number
US3806932A
US3806932A US00263230A US26323072A US3806932A US 3806932 A US3806932 A US 3806932A US 00263230 A US00263230 A US 00263230A US 26323072 A US26323072 A US 26323072A US 3806932 A US3806932 A US 3806932A
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Prior art keywords
array
elements
antenna
segment
switching
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Expired - Lifetime
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US00263230A
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English (en)
Inventor
R Martel
C Johnson
F Dietrich
G Koloboff
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National Aeronautics and Space Administration NASA
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Individual
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Priority to US00263230A priority Critical patent/US3806932A/en
Priority to GB2823173A priority patent/GB1423063A/en
Priority to CA173,927A priority patent/CA976247A/en
Priority to FR7321438A priority patent/FR2189888B1/fr
Priority to DE2330315A priority patent/DE2330315A1/de
Priority to JP48067659A priority patent/JPS4952553A/ja
Priority to NL7308350A priority patent/NL7308350A/xx
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Publication of US3806932A publication Critical patent/US3806932A/en
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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01Q—ANTENNAS, i.e. RADIO AERIALS
    • H01Q3/00—Arrangements for changing or varying the orientation or the shape of the directional pattern of the waves radiated from an antenna or antenna system
    • H01Q3/26—Arrangements for changing or varying the orientation or the shape of the directional pattern of the waves radiated from an antenna or antenna system varying the relative phase or relative amplitude of energisation between two or more active radiating elements; varying the distribution of energy across a radiating aperture
    • H01Q3/28—Arrangements for changing or varying the orientation or the shape of the directional pattern of the waves radiated from an antenna or antenna system varying the relative phase or relative amplitude of energisation between two or more active radiating elements; varying the distribution of energy across a radiating aperture varying the amplitude
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10S—TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10S343/00—Communications: radio wave antennas
    • Y10S343/02—Satellite-mounted antenna

Definitions

  • AMPLITUDE STEERED ARRAY [75] Inventors: Fred J. Dietrich, Palo Alto; George J. Koloboff, Foster City, both of Calif.; Robert J. Martel, Bel Air; Chester C. Johnson, Lanham, both of Md.
  • a spin stabilized satellite has an electronically despun antenna array comprising a multiplicity of peripheral antenna elements.
  • a high gain energy beam is estab- V lished by connecting a suitable fraction or array of the elements in phase.
  • the beam is steered or caused to scan by switching elements in sequence into one end of the array as elements at the other end of the array are switched out. The switching transients normally associated with such steering are avoided by an amplitude control system.
  • Satellites are stabilized in space by being caused to spin.
  • the spin axis is aligned with the spin axis of earth thereby causing the satellite to maintain a fixed orientation with respect to earth.
  • a high gain antenna is mounted on the satellite to provide communications with ground based stations, the antenna will be required to scan at the satellite rotation rate.
  • Such an antenna is said to be despun when its scan rate exactly equals the satellite spin rate.
  • a despun antenna can include a high gain array that is caused continuously to point toward earth.
  • the most common system employed at the higher or microwave frequencies comprises a ring array of antenna elements distributed about the periphery of the satellite.
  • the ring is concentric with the spin axis.
  • One method commonly employed to scan such an array is to vary or modulate the phase of the energy fed to the individual antennas.
  • phased signals will generate a beam that has the required characteristics and scans at the desired rate.
  • each element must be continuously visible from the desired direction of the beam. This is often impractical to implement, particularly where a high gain array is to be employed.
  • serious mechanical constraints are imposed as to the location of such an array on the satellite structure. Accordingly, many prior art antennas employ a combination of phase shifting and element switching to achieve the desired scanning.
  • the element spacing can be made such that when a small fraction or segment of the total number of elements is excited with an appropriate phase distribution, a suitable beam shape results.
  • antenna elements are sequentially switched into the driven segment as elements at the other end of the driven segment are switched out.
  • the driven segment advances around the satellite periphery as it rotates, thereby keeping the driven segment in a relatively constant position with respect to earth.
  • the incremental switching disconnects an antenna element from the trailing edge of the driven segment simultaneously with the addition of an element to the leading edge of the segment.
  • a constant number of elements always comprise the driven segment.
  • the switching sequence is such that first an element is switched into the segment at the leading edge, then an element is removed or disconnected from the trailing edge.
  • the antenna array comprises a number of elements spaced around the satellite periphery.
  • the array is designed so that when a small group or segment of adjacent elements is excited with r-f energy from a common source, the desired radiated beam pattern results.
  • the array is scanned by gradually transferring power from the receding element in the driven segment to the element next to the leading edge of the driven segment. Thus, constant power is applied to the array at all times and the beam is smoothly scanned around the satellite.
  • FIG. 1 shows a satellite with its scanned communications antenna array
  • FIG. 2 shows the detail of the individual sub array antenna elements
  • FIG. 3. shows the antenna element array geometry in terms of the scanning sequence
  • FIG. 4 is a timing diagram showing system operation
  • FIG. 5 is a block diagram showing the amplitude steering system
  • FIG. 6 shows the details of the single pole four throw (SP4T) switches of FIG. 5;
  • FIG. 7 shows the details of the variable power dividers of FIG. 5;
  • FIG. 8 shows the operating waveforms of one channel of the FIG. 5 system
  • FIG. 9 shows the geometry of motion of the array phase center of a conventional switched array
  • FIG. 10 shows amplitude and phase received on the ground from a conventional switched array as a function of spacecraft station.
  • FIG. 11 shows the amplitude and phase received on the ground from an amplitude-steered array as a function of spacecraft rotation.
  • FIG. 1 shows a satellite 40 that may be spin stabilized by means, not shown, that are well known in the art.
  • the communications antenna array is distributed around the outside of the lower portion 41.
  • the satellite 40 may contain sensors, power supplies, and other electronic equipment not shown.
  • the antenna portion, 41 of the satellite comprises 32 panels each containing a 4-antenna sub array.
  • FIG. 2 presents a detailed showing of each antenna sub array.
  • Coaxial feed line 42 drives folded dipole elements 43 and 44.
  • Parasitic directors 45 and 46 act in combination with the driven elements to provide substantial gain and directivity. Driven elements and directors are suitably supported on support mast 47 which, in turn, is supported in perpendicular relation on one of the 32 panels shown in FIG. 1.
  • the panel surface provides a ground plane for the sub array.
  • Four sub arrays are mounted on each panel. They are spaced and driven so as to generate a combined radiation pattern having the desired spatial distribution along the satellite spin axis. Since the four sub arrays on each panel are connected in an invariant manner, they will be regarded as a unit and each panel will hereinafter be referred to as a single antenna element.
  • FIG. 3 shows the relationship of the 32 elements located around the periphery of the antenna portion 41 of the satellite.
  • the satellite in this view is considered to spin counter clockwise and the antenna element switching sequence is in a clockwise direction.
  • elements 32, 1, and 2 each receive 5 watts of energy while elements 31 and 3 receive 2.5 watts each to produce a watt system.
  • the antenna element spacing around the satellite periphery is adjusted so that the above power distribution produces the desired antenna pattern with its major lobe pointing toward earth.
  • the antenna gain and beamwidth are optimized to illuminate earth with a high gain pattern.
  • the element feed is advanced clockwise around the array. Initially the power distribution between elements 31 and 3 is'shifted. The 5 watt input is maintained while the power to 3 is increased and the power to 31 is decreased. When element 3 reaches 5 watts and 31 reaches zero, the power applied to element 32 is descreased as the power to element 4 is increased.
  • phase centerjump in the conventional switch despun array occurs as a result of the geometry shown in FIG. 9.
  • the intersection of the array axis of symmetry, or phase center, with the spacecraft has a position relative to a point on earth which changes by as much as A1,, with time.
  • this position jumps suddenly by this amount, resulting in the phase patterns shown in FIG. 10.
  • the difference in phase between the end points of a given earth edge curve, say a +9 represents the amount of phase jump which will occur when the elements are abruptly switched.
  • the antenna phase center remains stationary in space, resulting in the performance shown in FIG. 11 as a function of satellite rotation. It can be seen there that the beginning and end phases at a +9", for example, are the same, so no phase jump will occur when switching takes place.
  • the peak-to-peak phase ripple is also substantially reduced when amplitude steering is used, being 9 in FIG. 11, compared to 40 in FIG. 10. This is also desirable for communication system performance.
  • FIG. 4 A partial timing diagram is shown in FIG. 4. The numbers are for an assumed spin of r.p.m. Time zero for this diagram represents the instant outlined above where elements 31 and 3 are at 2.5 watts. It can be seen from this timing diagram that the slope or rate of change in power is related to the total number of elements and that the power-versus-time function is relatively gradual for any particular element. It takes 18.75 milliseconds to shift the power level over the 5-watt range. Actual element switching is performed during the time interval when no power is being transferred, thereby avoiding switching transients.
  • FIG. 5 is a block diagram of a four channel system used to accomplish the antenna element switching and power control.
  • a transmitter source 50 provides signal energy to a 4-way power divider 51 which energizes a group of four power amplifiers 52 to 55. Each amplifier supplies 5 watts for a combined output of 20 watts.
  • amplifier 52 applies its output through diplexer 56 to variable power divider 60, the latter being illustrated in greater detail in FIG. 7.
  • the variable power divider will, depending upon the control voltage applied, apply the 5 watt signal to one of two switches 64 or 65 or both. In operation it will gradually transfer the power from one switch to the other.
  • the first single pole four throw (SP4T) switch 64 which is shown in greater detail in FIG.
  • SP4T switch 65 switches antenna elements 1, 9, 17 and 25 while SP4T switch 65 switches antenna elements 5, 13, 21, and 29. Switches 65 through 71 switch the remainder of the elements as shown. Thus the 32 elements are switched by eight SP4T switches. Pairs of SP4T switches are operated from four variable power dividers, each of which operates at a constant input power level.
  • time zero indicates the condition where power divider 62 has equal outputs to SP4T switches 68 and 69.
  • Switch 68 energizes element 3 and switch 69 energizes element 31.
  • Elements 32, 1, and 2 are all energized at a full 5 watts from switches 71, 64, and 66 respectively.
  • Power divider 60 is controlled to pass all of its input to switch 64 while power divider 61 is controlled to apply all of its power to switch 66 and power divider 63 is controlled to apply all of its power to switch 71.
  • the switching and power divider functions are all generated and controlled by the attitude determination and antenna control circuits 72 (referred to hereinafter as ADAC). These circuits are conventional and will not be described in detail. Attitude determination is usually a photoelectric process. Photoelectric detectors sense the earth location as a function of satellite rotation. This measurement also precisely indicates the spin rate. Alternately the sun can be sensed and the information on earth location computed therefrom. From these data the antenna control signals are generated. As will be apparent hereinafter, from the description of FIGS. 6, 7 and 8, the single line interconnecting ADAC device 72 and the eight SP4T switches in representative of a 32 circuit cable, four circuits to each of the eight SP4T switches. Similarly, the single line interconnecting ADAC device 72 and the four variable power dividers is representative of an eight circuit cable, two circuits to each of the variable power dividers.
  • the array will also function as a receiving antenna because the SP4T switches and variable power dividers are reciprocal devices. For a given antenna its receiving beam characteristics will approximate the transmitted beam characteristics. It is only necessary that the transmit and receive functions be separated slightly in frequency if it is desired to permit simultaneous operation or diplexing.
  • Diplexers 56-59 are included in the FIG. 5 circuits to provide the receiver function. These diplexers are well known conventional frequency selective devices. At the transmitting frequency the diplexers connect the power amplifiers to the variable power dividers. At the receiver frequency the diplexers connect the variable power dividers to combiner 73. Signals received by the various antenna elements will be connected, in accordance with the controls applied to the SP4T switches and power dividers, to combiner 73, the output of which is applied to a suitable receiver.
  • FIG. 6 shows the nature of the SP4T switches 64-71.
  • a common input terminal 74 receives signal energy from one of the two output terminals of one of the variable power dividers of FIG. 7 (i.e., from one of the output terminals, A or B, of FIG. 7).
  • Terminal 74 is coupled through a network comprising d-c blocking capacitor 75 and shunt d-c return indicator 76 to PIN diodes 77-80.
  • the diodes couple to output terminals 89-92 by way of impedance matching networks 85-88 which include d-c blocking capacitors.
  • Diode control signals derived from ADAC device 72 are applied through isolating inductors 81-84.
  • the characteristics of the PIN diodes 77-80 are such that when not biased they repre sent a high series impedance and will block transmission.
  • forward biased in the range of 75 to 200ma., they represent a very low impedance and will pass r-f energy.
  • the impedance matching networks are needed to correct for the physical discontinuity the diodes present in the r-f circuits.
  • signals at 74 will be transferred only to output 91.
  • the control circuits bias only one diode on at a time. Timing is controlled by ADAC device 72 so that the switching is accomplished during the interval when no r-f power is applied to the input terminal of the switch. Thus the switching action in the SP4T switches does not introduce transients into the signals being controlled.
  • FIG. 7 shows the nature of the variable power dividers 60-63.
  • two varactor diodes 93 and 94 couple two hybrids 95 and 96.
  • the unused terminal on hybrid 95 is terminated in a matched loan shown diagrammatically at 97.
  • Isolation inductors 98 and 99 permit control bias to be applied to the varactor coupling diodes.
  • the varactor diodes act as signal phase shifters and are operated with control voltages so that as the phase shift through one is increased, the phase shift through the other decreases.
  • the two output signals at A and B will be a function of the relative phase of the signals fed into hybrid 96. For the condition of equal phase inputs, where each varactor operates at a 45 phase shift, the outputs will be equal and of the same phase.
  • the relative outputs will vary, and if the control signals have the proper amplitude the output signals will be of constant phase at all levels.
  • the phase shift in diode 93 approaches zero the phase shift in diode 94 approaches For this condition all (or substantially all) of the output power appears at one output terminal while none (or at least very little) appears at the other output terminal. If the diode phase conditions are reversed, the output shifts to the other output terminal.
  • FIG. 7b shows how the output amplitude varies as a function of diode bias. It will be noted that as the control biases vary, the power division between outputs A and B varies disproportionately. If the inverse control signals have a suitable shape, as shown in FIG. 7b (and in the waveforms C1 and C2 of FIG. 8), division of input between the two outputs will be a linear function of time.
  • FIG. 8 is a partial showing of the switching waveforms required for antenna scanning. These are generated by conventional circuits in the ADAC section.
  • the bottom two waveforms C1 and C2 show the variable power divider control waveforms and would constitute the control 1 and control 2 signals of FIG. 7 as applied to variable power divider 62.
  • the transition waveform is shaped so that the actual transfer of output in the variable power dividers is linear (or nearly linear) with time.
  • the upper 8 waveforms of FIG. 8 are labelled in accordance with the antenna element activated through a SP4T switch by the upward-going portion of the waveform. The showing actually indicates the time sequence of element actuation or switching for the antenna elements associated with SP4T switches 68 and 69 of FIG.
  • a system for scanning a plurality of transducers located in a ring-shaped array comprising:
  • switching means for selectively and sequentially connecting transucers in said array to said common terminal so that only adjacent transducers in a segment of said array are connected to said common terminal at any given instant, control means operative on said switching means to cause said segment to scan around said array at a controlled rate, said segment including leading edge transducers and a trailing edge transducer,
  • variable coupling means in cascade between said switching means and said terminal
  • transducers are antennas and said controlled rate is the scanning rate of the antenna array.
  • a despun antenna operated on a spin stabilized satellite said antenna including an array of elements distributed to form a ring about the spin axis of said satellite, means for connecting a fraction of said elements into a segment of adjacent elements to produce a desired antenna pattern, said segment having a leading edge and a trailing edge, and means for switching elements into said leading edge of segment while switching elements out of said trailing edge of said segment at a rate equal to the spin rate of said satellite, the improvement comprising:

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  • Variable-Direction Aerials And Aerial Arrays (AREA)
  • Radio Relay Systems (AREA)
  • Aerials With Secondary Devices (AREA)
US00263230A 1972-06-15 1972-06-15 Amplitude steered array Expired - Lifetime US3806932A (en)

Priority Applications (7)

Application Number Priority Date Filing Date Title
US00263230A US3806932A (en) 1972-06-15 1972-06-15 Amplitude steered array
GB2823173A GB1423063A (en) 1972-06-15 1973-06-13 Scannable antenna array
CA173,927A CA976247A (en) 1972-06-15 1973-06-13 Amplitude steered antenna array
FR7321438A FR2189888B1 (GUID-C5D7CC26-194C-43D0-91A1-9AE8C70A9BFF.html) 1972-06-15 1973-06-13
DE2330315A DE2330315A1 (de) 1972-06-15 1973-06-14 Antennensystem
JP48067659A JPS4952553A (GUID-C5D7CC26-194C-43D0-91A1-9AE8C70A9BFF.html) 1972-06-15 1973-06-15
NL7308350A NL7308350A (GUID-C5D7CC26-194C-43D0-91A1-9AE8C70A9BFF.html) 1972-06-15 1973-06-15

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JP (1) JPS4952553A (GUID-C5D7CC26-194C-43D0-91A1-9AE8C70A9BFF.html)
CA (1) CA976247A (GUID-C5D7CC26-194C-43D0-91A1-9AE8C70A9BFF.html)
DE (1) DE2330315A1 (GUID-C5D7CC26-194C-43D0-91A1-9AE8C70A9BFF.html)
FR (1) FR2189888B1 (GUID-C5D7CC26-194C-43D0-91A1-9AE8C70A9BFF.html)
GB (1) GB1423063A (GUID-C5D7CC26-194C-43D0-91A1-9AE8C70A9BFF.html)
NL (1) NL7308350A (GUID-C5D7CC26-194C-43D0-91A1-9AE8C70A9BFF.html)

Cited By (12)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3993999A (en) * 1975-05-16 1976-11-23 Texas Instruments Incorporated Amplitude modulation scanning antenna system
US4121221A (en) * 1977-03-14 1978-10-17 Raytheon Company Radio frequency array antenna system
US4286267A (en) * 1978-03-31 1981-08-25 Siemens Aktiengesellschaft Directional antenna system with electronically controllable sweep of the beam direction
US4357608A (en) * 1980-09-03 1982-11-02 The United States Of America As Represented By The Secretary Of The Navy Scanning radar system
US4599619A (en) * 1982-07-13 1986-07-08 Rca Corporation Satellite dual antenna pointing system
US4924235A (en) * 1987-02-13 1990-05-08 Mitsubishi Denki Kabushiki Kaisha Holographic radar
US5940030A (en) * 1998-03-18 1999-08-17 Lucent Technologies, Inc. Steerable phased-array antenna having series feed network
US6483476B2 (en) * 2000-12-07 2002-11-19 Telex Communications, Inc. One-piece Yagi-Uda antenna and process for making the same
EP1473799A1 (fr) * 2003-04-30 2004-11-03 Alcatel Satellite à couverture multi-zones assurée par deviation de faisceau
US20090033575A1 (en) * 2004-06-17 2009-02-05 The Aerospace Corporation System and method for antenna tracking
WO2022048772A1 (en) 2020-09-04 2022-03-10 Fraunhofer-Gesellschaft zur Förderung der angewandten Forschung e.V. Method and apparatus for designing a phased array antenna, phased array antenna and method for operating a phased array antenna
US20220393340A1 (en) * 2021-06-04 2022-12-08 Raytheon Company Rotating multi-beam antenna

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3044063A (en) * 1959-03-19 1962-07-10 Alford Andrew Directional antenna system
US3531803A (en) * 1966-05-02 1970-09-29 Hughes Aircraft Co Switching and power phasing apparatus for automatically forming and despinning an antenna beam for a spinning body
US3707719A (en) * 1970-04-18 1972-12-26 Marconi Co Ltd Scanning aerial systems and associated arrangements therefor

Family Cites Families (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3015800A (en) * 1955-07-15 1962-01-02 John F Jewett Electronic scanning switch

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3044063A (en) * 1959-03-19 1962-07-10 Alford Andrew Directional antenna system
US3531803A (en) * 1966-05-02 1970-09-29 Hughes Aircraft Co Switching and power phasing apparatus for automatically forming and despinning an antenna beam for a spinning body
US3707719A (en) * 1970-04-18 1972-12-26 Marconi Co Ltd Scanning aerial systems and associated arrangements therefor

Cited By (18)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3993999A (en) * 1975-05-16 1976-11-23 Texas Instruments Incorporated Amplitude modulation scanning antenna system
US4121221A (en) * 1977-03-14 1978-10-17 Raytheon Company Radio frequency array antenna system
US4286267A (en) * 1978-03-31 1981-08-25 Siemens Aktiengesellschaft Directional antenna system with electronically controllable sweep of the beam direction
US4357608A (en) * 1980-09-03 1982-11-02 The United States Of America As Represented By The Secretary Of The Navy Scanning radar system
US4599619A (en) * 1982-07-13 1986-07-08 Rca Corporation Satellite dual antenna pointing system
US4924235A (en) * 1987-02-13 1990-05-08 Mitsubishi Denki Kabushiki Kaisha Holographic radar
US5940030A (en) * 1998-03-18 1999-08-17 Lucent Technologies, Inc. Steerable phased-array antenna having series feed network
US6483476B2 (en) * 2000-12-07 2002-11-19 Telex Communications, Inc. One-piece Yagi-Uda antenna and process for making the same
EP1473799A1 (fr) * 2003-04-30 2004-11-03 Alcatel Satellite à couverture multi-zones assurée par deviation de faisceau
FR2854503A1 (fr) * 2003-04-30 2004-11-05 Cit Alcatel Satellite a couverture multi-zones assuree par deviation de faisceau
WO2004100306A3 (fr) * 2003-04-30 2005-01-13 Cit Alcatel Satellite a couverture multi-zones assuree par deviation de faisceau
US20060119504A1 (en) * 2003-04-30 2006-06-08 Freddy Maquet Satellite with multi-zone coverage obtained by beam deviation
US7545315B2 (en) 2003-04-30 2009-06-09 Thales Satellite with multi-zone coverage obtained by beam deviation
CN1781215B (zh) * 2003-04-30 2011-06-29 阿尔卡特公司 具有通过射束偏移所获得的多区域覆盖的卫星
US20090033575A1 (en) * 2004-06-17 2009-02-05 The Aerospace Corporation System and method for antenna tracking
WO2022048772A1 (en) 2020-09-04 2022-03-10 Fraunhofer-Gesellschaft zur Förderung der angewandten Forschung e.V. Method and apparatus for designing a phased array antenna, phased array antenna and method for operating a phased array antenna
US20220393340A1 (en) * 2021-06-04 2022-12-08 Raytheon Company Rotating multi-beam antenna
US11923604B2 (en) * 2021-06-04 2024-03-05 Raytheon Company Rotating multi-beam antenna

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Publication number Publication date
JPS4952553A (GUID-C5D7CC26-194C-43D0-91A1-9AE8C70A9BFF.html) 1974-05-22
GB1423063A (en) 1976-01-28
DE2330315A1 (de) 1974-01-03
NL7308350A (GUID-C5D7CC26-194C-43D0-91A1-9AE8C70A9BFF.html) 1973-12-18
FR2189888B1 (GUID-C5D7CC26-194C-43D0-91A1-9AE8C70A9BFF.html) 1978-02-10
CA976247A (en) 1975-10-14
FR2189888A1 (GUID-C5D7CC26-194C-43D0-91A1-9AE8C70A9BFF.html) 1974-01-25

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