EP0325012A1 - Phasengesteuerte Antenne mit Kopplern, die zu einem örtlich koppelndem Filter angordnet sind - Google Patents

Phasengesteuerte Antenne mit Kopplern, die zu einem örtlich koppelndem Filter angordnet sind Download PDF

Info

Publication number
EP0325012A1
EP0325012A1 EP88300427A EP88300427A EP0325012A1 EP 0325012 A1 EP0325012 A1 EP 0325012A1 EP 88300427 A EP88300427 A EP 88300427A EP 88300427 A EP88300427 A EP 88300427A EP 0325012 A1 EP0325012 A1 EP 0325012A1
Authority
EP
European Patent Office
Prior art keywords
predetermined ratio
ports
output port
input
output
Prior art date
Legal status (The legal status 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 status listed.)
Granted
Application number
EP88300427A
Other languages
English (en)
French (fr)
Other versions
EP0325012B1 (de
Inventor
Alfred R. Lopez
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
BAE Systems Aerospace Inc
Original Assignee
Hazeltine Corp
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 Hazeltine Corp filed Critical Hazeltine Corp
Priority to EP19880300427 priority Critical patent/EP0325012B1/de
Priority to DE19883885082 priority patent/DE3885082T2/de
Publication of EP0325012A1 publication Critical patent/EP0325012A1/de
Application granted granted Critical
Publication of EP0325012B1 publication Critical patent/EP0325012B1/de
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

Links

Images

Classifications

    • 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
    • H01Q3/30—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 relative phase between the radiating elements of an array
    • H01Q3/34—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 relative phase between the radiating elements of an array by electrical means
    • H01Q3/40—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 relative phase between the radiating elements of an array by electrical means with phasing matrix

Definitions

  • This invention relates to array antenna systems and particularly to such systems wherein the antenna element pattern is modified by providing a iossless spatial filter between the antenna input ports and the antenna elements so that the effective element pattern associated with each input port is primarily within a selected angular region of space.
  • An array antenna system may be designed to transmit a desired radiation pattern into one of a plurality of angular directions in a selected region of space.
  • each of the antenna elements has an associated input port.
  • the antenna pattern can be electronically steered in space to point in a desired radiation direction or otherwise controlled to radiate a desired signal characteristic, such as a time reference beam scanning pattern.
  • the radiation pattern of the individual antenna elements also be primarily within the selected angular region. This permits maximum element spacing while suppressing undesired grating !obes.
  • control of the element pattern by modification of the physical shape of the antenna element may be impractical because of a desired element pattern may require an element aperture size which exceeds the necessary element spacing In the array.
  • a practical approach to overcome the physical elements size limitation is to provide networks for interconnecting each antenna input port with more than the antenna element. so that the effective element pattern associated with each input port is formed by the composite radiation of several elements. These networks can be realized by printed circuit techniques using a single substrate layer.
  • Nemit achieves a larger effective element size by providing intermediate antenna elements between the primary antenna elements and coupling signals from the primary antenna element ports to the intermediate element ports. This tapered multielement aperture excitation produces some measure of control over the radiated antenna pattern.
  • a more effective prior art antenna coupling network is descnbed by Frazita et al. in U.S. Patent No. 4 041 501 incorporated herein by reference and assigned to the same assignee as the present invention.
  • the antenna elements are arranged m element modules, each module is provided with an input port. Transmission lines are coupled to all of the antenna element modules in the array. The transmission lines couple signals applied to any of the ports to selected elements in all the antenna element modules of the array.
  • This antenna herein referred to as a COMPACT antenna, provides an effective element aperture which is coextensive with the array aperture.
  • U.S. Patent No. 4.168.503 which describes an antenna array with a printed circuit lens in a coupling network.
  • the lens comprises a plurality of vertically standing and circularly arranged printed circuit panels. each of which modudes a conductor strip connected at one end to each antenna.
  • a plurality of semi-elliptical circuit panels are affixed to the vertical panels at a predetermined angle.
  • Metal strips plated on the semi-elliptical panels provide the desired time delay to the antenna signals.
  • a combining strip couples the time delay strips and provides a combined output signal at one end of the semi-elliptical pattern.
  • the angle at which the semi-elliptical boards are affixed to the vertical boards corrects for time delay distortion caused by the placement of the compring strip. This configuration cannot be implemented using printed circuit techniques on a single substrate layer.
  • U.S. Patent No. 4.321.605 descnbes an array antenna system having at least a 2:1 ratio of antenna elements to input terminals interconnected via primary transmission lines. Secondary transmission lines are coupled to and intersecting a selected number of the primary transmission lines. Signals supplied to any of the input terminals are coupled pnmarily to the elements corresponding to the input terminal, and are also occupied to other selected elements.
  • time reference scanning beam systems such as microwave landing systems (MLS)
  • MLS microwave landing systems
  • this invention provides a non-thinned or fully filled array which may be used to achieve linearity and minimize the field monitor distance.
  • the antenna system radiates wave energy signals into a selected angular region of space and into a desired radiation pattern.
  • the system includes a lossless spatial filter having N input ports and N output parts.
  • the aperture of the system comprises a plurality of N antenna elements.
  • the antenna elements are arranged along a predetermined path and each element is connected to only one output port of the spatial filter.
  • a beam steering unit controls the direction of radiation and includes N phase shifters and means for controlling of phase shifters.
  • Each phase shifter has a phase shifter input port and a phase shifter output port which is connected to only one input port of the spatial filter.
  • the antenna also includes a supply means for supplying wave energy signals.
  • the supply means includes a signal generator supplying a power divider having N output signal ports, each output port connected to only one phase softer input port.
  • FIG. 1 is a schematic diagram illustrating an antenna system in accordance N ith the present invention.
  • the diagram of Figure 1 includes a plurality of antenna elements 1-8 arranged in a predetermined path which. in this case, is a straight line.
  • Each antenna element is connected to one and only one output port 9-16 of spatial filter 17.
  • the spatial filter is comprised of a plurality of modules A through H, one module for each antenna element.
  • Spatial filters 17 includes 8 input ports. 18-25 each connected to the output of one and only one phase shifter 26-33.
  • the array of phase shifters 26-33 form beam steering unit 34.
  • the inputs 35-42 of the phase shifters are connected to one and only one output of power divider 43 which is fed by signal generator 44.
  • the power divider and signal generator form a supply means for supplying Nave energy signals.
  • filter 17 has been illustrated as symmetrical, it is contemplated that spatial filters according to the invention may be unsymmetncal.
  • the original signal is provided via line 45 to power divider 43 which divides the signal into eight equal components.
  • Each component is provided via lines 46-53 to only one input of beam steering unit 34.
  • line 46 provides the signal component to input 35 of beam steering unit 34.
  • the component then passes through phase shifter 26 which may shift the phase of the component according to instructions received from control unit 54 via control line 55.
  • the output of phase shifter 26 is provided to input port 18 of spatial filter 17
  • the signal component provided to input port 18 is provided to output port 9 which is connected to antenna element 1 and is also provided by a coupling arrangement to element 2 which is adjacent to antenna element 1.
  • Spatial filter 17 couples component signals which are provided to any input to the antenna element associated with the input and to elements adjacent to the associated element. Couplers 56-62 couple signals which are provided to an associated antenna element to the antenna element which is to the left of the associated antenna element.
  • the component signal provided to an input is transmitted to the antenna element associated with the input by transmission lines 64-71.
  • the component signal provided by branch 39 of the power divider 43 is fed through phase shifter 30 and provided to input 22 of spatial after 17.
  • input 22 is connected by transmission nne 68 to its associated output 13 and antenna element 5.
  • the component signal is also coupled by coupler 59 to antenna element 4 which is to the left of and adjacent to antenna element 5.
  • component signals provided to an input are also coupled to antenna elements adjacent and right of the associated antenna element by couplers 72-80.
  • the component signal provided by branch 49 of the power divider to input 38 of phase shifter 29 passes through phase shifter 29 and is provided to input 21 of the spatial filter 17.
  • the component signal is then provided to output 12 by transmission line 67.
  • Output 12 is directly connected to antenna element 4.
  • Element 5 is adjacent to and to the right of antenna element 4 and receives a portion of the component signal via coupler 76.
  • Element 3 is adjacent to and to the left of antenna element 4 and receives a portion of the component signal via coupler 58.
  • Spatial filter 17 is shown in modular form. As a result, the input to coupler 72 is terminated by termination 81 because there is no antenna element to the left of antenna element 1. Similarly. the output from coupler 56 is terminated by termination 82 because there is no antenna element to the left of antenna element 1 to receive the component signal provided to input 18. On the right side of spatial filter 17. coupler 80 is terminated by termination 83 and coupler 63 is terminated by termination 84 because there is no antenna element to the right of antenna element 8 to receive the couple signal from coupler 80 or to provide a coupled signal via coupler 63.
  • Figure 2 illustrates a plan view of a printed circuit coupling network useful as the spatial filter 17 of Figure 1.
  • Network 17 includes input ports 18-25 connected to the outputs of beam steering unit 34. These rout ports are connected to a first series of couplers C. shown in detail in Figure 2A.
  • Coupler C, as well as all other couplers may be standard microstrip network couplers having a predetermined coupling ratio. The specific coupling ratio depends on the width, length and on the thickness of the transmission lines within the coupler.
  • signals provided to the inputs 101 and 102 of coupler C are coupled to the outputs 103 and 104 according to a predetermined ratio.
  • Couplers 109-116 work in the same manner as coupler C, as shown in Figure 2A by combining signals provided to their inputs to the outputs 9-16 of spatial filter 17.
  • spatial filter 17 is ideally lossless (except for dissipative losses) and for that reason the relationships must apply to the power (voltage) passing through each coupler C 1 and T 1 . respectively.
  • the following relationship ensures the lossless condition for the network:
  • This relationship can be derived by setting the inputs at 18-25 equal to unity and the inputs to the terminations 117-124 equal to zero.
  • a non-thinned spatial filter is a filter formed by an array of couplers.
  • the array is essentially lossless in that the power dissipated within terminations is minimized.
  • FIG 3 is a schematic diagram of an antenna system in accordance with the invention including a three four level cascaded spatial filter 300.
  • this spatial filter may be used in combination with the antenna system as shown in Figure 1 by replacing spatial filter 17 with spatial filter 300.
  • Each antenna element 1-8 would then be connected to one and only one output port 301 of the spatial filter 300.
  • Spatial filter 300 is comprised of a plurality of modules A through H, one module for each antenna element.
  • Spatial filter 300 includes input ports 302 each connected to one and only one of the outputs of a phase shift network.
  • Figure 4 is a plan view of a printed circuit coupling network of the cascaded spatial filter 300 illustrated in Figure 3.
  • Figure 5A illustrates an ideal antenna pattern for an antenna according to the invention employing spatial filters having a two level coupling. Essentially this coupling creates lobes 501, 502 and 503.
  • Figure 58 illustrates a typical antenna pattern employing a three level spatial filter which forms a single lobe 504.
  • Figure 5C illustrates a typical antenna pattern for a four level spatial filter generating a more well defined single lobe 505.
  • step 2-5 result in:
  • the db loss (from step 8) between the normalized actual excitations (from step 5) and the desired excitations (from step 1 a) is:
  • trial 5 illustrates an optimum arrangement with minimum power loss.
  • the design of a spatial filter involves the determination of coupler values for a multilayer circuit. No closed form solution is readily apparent to the synthesis of a network that produces a specified output voltage distribution. However, analysis of any network is possible. Therefore, synthesis involves the iterative tral and error procedure described above in which coupler values are gradually adjusted until the desired outputs are achieved.
  • the theoretical loss of a spatial filter network is determined by conservation of power considerations.
  • the network prototype is shown in Figure 7.
  • the network is symmetrical and continues to infinity in both directions.
  • Each input excites a sub array with N outputs.
  • the sub array outputs resulting from adjacent routs. overlap.
  • the network shown in Figure 7 has an equal number of inputs and outputs. Therefore, the input and output spacings are equal and, when all inputs are excited, each output port will be the sum of contributions from N input ports. There must be an internal termination for each output port.
  • Bj(N) the power terminated
  • the A's and B's are voltage coefficients.
  • the power at each output port is equal to the square of the voltage coefficient when the system impedance is normalized to one ohm.
  • the network When that condition is met, the network will be lossless when all input ports are excited with equal amplitude and phase.
  • the loss, when a single input port is excited and the sub array pattern has a maximum in the in-phase direction, is given by:
  • the lower bound on the loss is increased by the difference in the sub array gain in the two directions.
  • the optimum network is one that provides the least loss.
  • the loss that can be expected is the difference between the computed network loss and the theoretical value.
  • the basic spatial filter network topologies are well-known. A preferred implementation requires 17 layers and is nearly impossible to synthesize. A practical network. that closely approximates the performance of a 17-layer network, uses two cascaded 8-layer networks as illustrated in Figure 8. The pattern characteristics for this network are shown in Figures 9 and 10 for a radiating element spacing of 0.79 wavelengths.
  • Figure 11 describes the linearity requirement for MLS glide path guidance.
  • the discussion of linearity concentrates on the elevation guidance performance, however, linearity is also a requirement for the azimuth guidance.
  • Linearity is a subject that has generated much discussion in the MLS community.
  • the invention provides a phased array antenna which meets the elevation linearity requirement.
  • the spatial filter network is a practical way to satisfy the low effective sidelobe requirement which is directly related to the linearity requirement.
  • the linearity (autopilot) requirement limits the deviation from the ideal linear relationship of the MLS guidance angle and the actual angle (see Figure 11 It specifies the transverse accuracy characteristic of the angle guidance signal as opposed to the longitudinal characteristics of PFN and CMN.
  • the longitudinal characteristic causes the aircraft to deviate from the glide path (bends) or generates noise-like action of the controls.
  • the transverse characteristic is capable of causing instability in an automatic flight control system.
  • PFN Path Following Noise
  • the effective sidelobe level required to ensure that the PFN for a 1.5° beamwidth antenna does not exceed 0.083° is -25 dB (a 0 dB ground reflection coefficient is assumed, the 0.083° PFN limit is derived from the ICAO standard that the PFN shall not be greater than plus or minus 1.3 feet).
  • the effective sidelobe level is specified such that the CMN does not exceed 0.045° This requires an effective sidelobe level of -30 dB for a 1.5° b eamwidth antenna.
  • the sidelobes radiated by the elevation antenna in the direction of the ground are folded back on the main beam because of specular reflection.
  • the side lobe radiation distorts the beam and causes PFN, CMN and linearity errors.
  • the specification of PFN and CMN limits the magnitude of the angle guidance error.
  • the linearity error depends on the product of the maximum angle guidance error and the height of the antenna phase center above the reflecting ground surface.
  • a large error-height product is capable of causing substantial degradation of the guidance loop gain of an automatic flight control system to the point where the automatic flight control system becomes unstable. For example, a maximum error of 0.045° and a phase center height of 20 feet can cause the loop gain to vary between +6 dB and less than -40 dB (at the "max gain spot" and the "dead spot”. see Figure 11).
  • Figures 13. 14 and 15 provide a summary of the simulation results with respect to the allowable peak MLS guidance error, elevation antenna phase center height and passenger comfort. The simulations start at a distance of 3 NM from the elevation antenna.
  • Figure 13 shows that for a 20 feet phase center height and a peak error of 0.083' the automatic control system is unstable.
  • the vertical accelerations exceed the passenger comfort level by a factor of 2.4:1.
  • peak error of 0.045 . the system is marginally stable: for larger phase center heights, say 37 feet, it is expected that the system would be unstable (the error-height product, 0.045° X 37 , is equal to that of the 0.083 maximum error and 20 feet height case).
  • Figures 14 and 15 exhibit the same trends: they show that for a 20 feet phase center height and a peak error of 0.083° the vertical velocity and attitude exceed the passenger comfort levels by factors of 4:1 and 2:1 respectively.

Landscapes

  • Variable-Direction Aerials And Aerial Arrays (AREA)
EP19880300427 1988-01-20 1988-01-20 Phasengesteuerte Antenne mit Kopplern, die zu einem örtlich koppelndem Filter angordnet sind Expired - Lifetime EP0325012B1 (de)

Priority Applications (2)

Application Number Priority Date Filing Date Title
EP19880300427 EP0325012B1 (de) 1988-01-20 1988-01-20 Phasengesteuerte Antenne mit Kopplern, die zu einem örtlich koppelndem Filter angordnet sind
DE19883885082 DE3885082T2 (de) 1988-01-20 1988-01-20 Phasengesteuerte Antenne mit Kopplern, die zu einem örtlich koppelndem Filter angordnet sind.

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
EP19880300427 EP0325012B1 (de) 1988-01-20 1988-01-20 Phasengesteuerte Antenne mit Kopplern, die zu einem örtlich koppelndem Filter angordnet sind

Publications (2)

Publication Number Publication Date
EP0325012A1 true EP0325012A1 (de) 1989-07-26
EP0325012B1 EP0325012B1 (de) 1993-10-20

Family

ID=8199929

Family Applications (1)

Application Number Title Priority Date Filing Date
EP19880300427 Expired - Lifetime EP0325012B1 (de) 1988-01-20 1988-01-20 Phasengesteuerte Antenne mit Kopplern, die zu einem örtlich koppelndem Filter angordnet sind

Country Status (2)

Country Link
EP (1) EP0325012B1 (de)
DE (1) DE3885082T2 (de)

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP3419104A1 (de) * 2017-06-22 2018-12-26 CommScope Technologies LLC Systeme zur zellularen kommunikation mit darin enthaltenen antennenarrays mit verbesserter steuerung der halben leistungsstrahlbreite (hpbw)
US10879605B2 (en) 2018-03-05 2020-12-29 Commscope Technologies Llc Antenna arrays having shared radiating elements that exhibit reduced azimuth beamwidth and increase isolation
CN113315550A (zh) * 2020-02-27 2021-08-27 上海华为技术有限公司 天线系统和接入网设备
US11342668B2 (en) 2017-06-22 2022-05-24 Commscope Technologies Llc Cellular communication systems having antenna arrays therein with enhanced half power beam width (HPBW) control
US11417944B2 (en) 2020-02-13 2022-08-16 Commscope Technologies Llc Antenna assembly and base station antenna including the antenna assembly

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2024118325A1 (en) * 2022-12-01 2024-06-06 Commscope Technologies Llc Multibeam sector-splitting base station antennas having modified nolen matrix-based beamforming networks

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4041501A (en) * 1975-07-10 1977-08-09 Hazeltine Corporation Limited scan array antenna systems with sharp cutoff of element pattern
US4143379A (en) * 1977-07-14 1979-03-06 Hazeltine Corporation Antenna system having modular coupling network
US4321605A (en) * 1980-01-29 1982-03-23 Hazeltine Corporation Array antenna system
EP0215971A1 (de) * 1985-09-24 1987-04-01 Allied Corporation Antenne speisendes Netzwerk

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4041501A (en) * 1975-07-10 1977-08-09 Hazeltine Corporation Limited scan array antenna systems with sharp cutoff of element pattern
US4143379A (en) * 1977-07-14 1979-03-06 Hazeltine Corporation Antenna system having modular coupling network
US4321605A (en) * 1980-01-29 1982-03-23 Hazeltine Corporation Array antenna system
EP0215971A1 (de) * 1985-09-24 1987-04-01 Allied Corporation Antenne speisendes Netzwerk

Cited By (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP3419104A1 (de) * 2017-06-22 2018-12-26 CommScope Technologies LLC Systeme zur zellularen kommunikation mit darin enthaltenen antennenarrays mit verbesserter steuerung der halben leistungsstrahlbreite (hpbw)
CN109119765A (zh) * 2017-06-22 2019-01-01 康普技术有限责任公司 含带增强半功率波束宽度控制的天线阵列的蜂窝通信系统
US10840607B2 (en) 2017-06-22 2020-11-17 Commscope Technologies Llc Cellular communication systems having antenna arrays therein with enhanced half power beam width (HPBW) control
US11342668B2 (en) 2017-06-22 2022-05-24 Commscope Technologies Llc Cellular communication systems having antenna arrays therein with enhanced half power beam width (HPBW) control
US10879605B2 (en) 2018-03-05 2020-12-29 Commscope Technologies Llc Antenna arrays having shared radiating elements that exhibit reduced azimuth beamwidth and increase isolation
US11417944B2 (en) 2020-02-13 2022-08-16 Commscope Technologies Llc Antenna assembly and base station antenna including the antenna assembly
CN113315550A (zh) * 2020-02-27 2021-08-27 上海华为技术有限公司 天线系统和接入网设备
CN113315550B (zh) * 2020-02-27 2022-03-29 上海华为技术有限公司 天线系统和接入网设备

Also Published As

Publication number Publication date
DE3885082D1 (de) 1993-11-25
EP0325012B1 (de) 1993-10-20
DE3885082T2 (de) 1994-05-11

Similar Documents

Publication Publication Date Title
US5003314A (en) Digitally synthesized phase error correcting system
Agrawal et al. Beamformer architectures for active phased-array radar antennas
JP2629057B2 (ja) 自己監視・較正フェイズドアレーレーダ
JP5583267B2 (ja) モジュラ能動開口電子指向性アレイのためのｒｆ給電ネットワーク
DE69113493T2 (de) Aktives Antennensystem in gedruckter Schaltungstechnik mit hohem Wirkungsgrad für ein gesteuertes Weltraum-Radargerät.
US5477229A (en) Active antenna near field calibration method
US4876548A (en) Phased array antenna with couplers in spatial filter arrangement
EP0647358B1 (de) System zur verteilung elektromagnetischer energie
JP2013529411A5 (de)
CA1164087A (en) Array antenna system
CN112688073B (zh) 反射式多波束卫星通信平板阵列天线控制系统及仿真方法
Casini et al. A novel design method for Blass matrix beam-forming networks
US5333002A (en) Full aperture interleaved space duplexed beamshaped microstrip antenna system
US4918457A (en) Antenna formed of strip transmission lines with non-conductive coupling
US6384782B2 (en) Antenna arrangement and method for side-lobe suppression
US6094172A (en) High performance traveling wave antenna for microwave and millimeter wave applications
EP0325012A1 (de) Phasengesteuerte Antenne mit Kopplern, die zu einem örtlich koppelndem Filter angordnet sind
US4746923A (en) Gamma feed microstrip antenna
EP0275303B1 (de) Halbleiter phasengesteuerte gruppenantenne mit kleinen nebenkeulen
GB1600346A (en) Antenna system having modular coupling network
US5289196A (en) Space duplexed beamshaped microstrip antenna system
CA1296098C (en) Phased array antenna with couplers in spatial filter arrangement
JP2720972B2 (ja) 空間フイルタ構成のカップラを有する整相アレイアンテナ
Bonnedal et al. A dual beam slotted waveguide array antenna for SAR applications
CN215816403U (zh) 一种四波束多普勒雷达微带平面阵列天线

Legal Events

Date Code Title Description
PUAI Public reference made under article 153(3) epc to a published international application that has entered the european phase

Free format text: ORIGINAL CODE: 0009012

AK Designated contracting states

Kind code of ref document: A1

Designated state(s): DE FR GB IT

17P Request for examination filed

Effective date: 19890920

17Q First examination report despatched

Effective date: 19920207

GRAA (expected) grant

Free format text: ORIGINAL CODE: 0009210

AK Designated contracting states

Kind code of ref document: B1

Designated state(s): DE FR GB IT

ITF It: translation for a ep patent filed

Owner name: JACOBACCI CASETTA & PERANI S.P.A.

REF Corresponds to:

Ref document number: 3885082

Country of ref document: DE

Date of ref document: 19931125

ET Fr: translation filed
PLBE No opposition filed within time limit

Free format text: ORIGINAL CODE: 0009261

STAA Information on the status of an ep patent application or granted ep patent

Free format text: STATUS: NO OPPOSITION FILED WITHIN TIME LIMIT

26N No opposition filed
PGFP Annual fee paid to national office [announced via postgrant information from national office to epo]

Ref country code: DE

Payment date: 19970327

Year of fee payment: 10

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: DE

Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES

Effective date: 19981001

PGFP Annual fee paid to national office [announced via postgrant information from national office to epo]

Ref country code: FR

Payment date: 19991223

Year of fee payment: 13

PGFP Annual fee paid to national office [announced via postgrant information from national office to epo]

Ref country code: GB

Payment date: 19991229

Year of fee payment: 13

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: GB

Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES

Effective date: 20010120

GBPC Gb: european patent ceased through non-payment of renewal fee

Effective date: 20010120

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: FR

Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES

Effective date: 20010928

REG Reference to a national code

Ref country code: FR

Ref legal event code: ST

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: IT

Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES;WARNING: LAPSES OF ITALIAN PATENTS WITH EFFECTIVE DATE BEFORE 2007 MAY HAVE OCCURRED AT ANY TIME BEFORE 2007. THE CORRECT EFFECTIVE DATE MAY BE DIFFERENT FROM THE ONE RECORDED.

Effective date: 20050120