Classifications

• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01Q—ANTENNAS, i.e. RADIO AERIALS
  • H01Q21/00—Antenna arrays or systems
  • H01Q21/06—Arrays of individually energised antenna units similarly polarised and spaced apart
  • H01Q21/061—Two dimensional planar arrays
  • H01Q21/065—Patch antenna array
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01Q—ANTENNAS, i.e. RADIO AERIALS
  • H01Q1/00—Details of, or arrangements associated with, antennas
  • H01Q1/12—Supports; Mounting means
  • H01Q1/22—Supports; Mounting means by structural association with other equipment or articles
  • H01Q1/24—Supports; Mounting means by structural association with other equipment or articles with receiving set
  • H01Q1/247—Supports; Mounting means by structural association with other equipment or articles with receiving set with frequency mixer, e.g. for direct satellite reception or Doppler radar
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01Q—ANTENNAS, i.e. RADIO AERIALS
  • H01Q23/00—Antennas with active circuits or circuit elements integrated within them or attached to them
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01Q—ANTENNAS, i.e. RADIO AERIALS
  • H01Q9/00—Electrically-short antennas having dimensions not more than twice the operating wavelength and consisting of conductive active radiating elements
  • H01Q9/04—Resonant antennas
  • H01Q9/0407—Substantially flat resonant element parallel to ground plane, e.g. patch antenna
  • H01Q9/0428—Substantially flat resonant element parallel to ground plane, e.g. patch antenna radiating a circular polarised wave
  • H01Q9/0435—Substantially flat resonant element parallel to ground plane, e.g. patch antenna radiating a circular polarised wave using two feed points
• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04B—TRANSMISSION
  • H04B1/00—Details of transmission systems, not covered by a single one of groups H04B3/00 - H04B13/00; Details of transmission systems not characterised by the medium used for transmission
  • H04B1/06—Receivers
  • H04B1/16—Circuits
  • H04B1/18—Input circuits, e.g. for coupling to an antenna or a transmission line

Definitions

• the present invention refers to a method and an arrangement for receiving and mixing electromagnetic waves, which arrangement includes an antenna element and an amplifying transistor.
• the incoming information is received as a radio frequency (RF) signal, which can be divided into a known portion (carrier wave) and an information carrying portion.
• LO which is a locally generated signal is sent to a non-linear component together with the RF signal, which results in addition of RF and LO.
• a voltage powered transistor converts the product RF x LO to a current I RJ . X I L0 , the phase and amplitude of which corresponds to the information carrying portion of the RF signal. This is comparable to a frequency translation in the frequency plane. Normally, one is interested of the product If ⁇ - f L0
• EP-A1 -762530 describes a broadband, high temperature superconductive mixer antenna, which allows a superconductive power line exhibiting a high-resistance loss in the high-frequency region. This can be used in the low-frequency region with low loss.
• the invention according to this document can only be used in very low temperatures (in best case liquid hydrogen temperature) which does not suit the use in normal applications.
• SIS Superconductive-Insulator-Superconductive junction
• One object of the present invention is to reduce the LO power, for example to less than a tenth compared to conventional techniques, which results in production of more compact, cheaper and less power consuming system realizations.
• Another object of the invention is to minimize the LO power, which leaks out from the system.
• one object of the invention is to provide a sensor with reduced noise factor compared with earlier prior art, which increases the sensitivity of the sensor. Through the invention, at a certain noise level and LO power higher frequency can be used.
• the invention employs a high-frequency FET (Field Effect Transistor) as a non-linear mixer, which allows normal temperature applications.
• FET Field Effect Transistor
• a good amplifying is obtained and LO need is reduced, for example at 10 dB amplifying the necessary LO effect may be 20 dB.
• the method according to the invention for a receiver of electromagnetic waves which comprises an antenna element and an amplifier unit for mixing and amplifying the received signals is characterized by carrying out the mixing and amplifying functions at least in one and the same transistor.
• Fig. 1 is a schematic, very simplified circuit diagram of one embodiment, according to the present invention .
• Fig. 2 is a schematic layout over one embodiment, according to the present invention, in so-called microstrip technique.
• Fig. 3 is a schematic circuit diagram for the layout shown in fig. 2.
• Fig. 4 is a schematic and slightly simplified matrix including the device shown in fig. 2.
• the invention may be a part of a radar receiver and especially a part of a micro or extremely high frequency sensor comprising a receiver integrated in an antenna, which is build by means of so-called active "gate-mixer", which is based on an active component (amplifying transistor) of FET (Field Effect Transistor) , HEMT (High Electron Mobility Transistor), BJT (Bipolar Junction Transistor), HBT (Hetrostructure Bipolar Transistor) or the like.
• active component amplifying transistor
• FET Field Effect Transistor
• HEMT High Electron Mobility Transistor
• BJT Bipolar Junction Transistor
• HBT Hybristructure Bipolar Transistor
• Fig. 1 shows schematically the operation principle of the transistor 10 and its circuit diagram.
• the local oscillation (LO) and the radio frequency (RF) are applied to the gate electrode 11.
• the intermediate frequency IF i.e., the difference between RF and LO is produced at the drain electrode 12 of the transistor.
• the transistor is Supplied with Direct Current (DC) at the drain electrode 12.
• DC Direct Current
• the gate 11 of the transistor is supplied with DC.
• Vg By varying the gate voltage Vg s a maximal conversion gain is obtained.
• the source 13 is grounded.
• the RF and LO signals are combined in the antenna element and then applied to the gate electrode of the amplifying transistor.
• the transistor can either be connected in "active mode” or in "ground gate mode", so that the transistor amplifies the frequency at the mixer operation point. Because both LO and RF signals are applied to the gate electrode, both LO and RF will be amplified in the transistor element, which means that the LO signal can have relatively low amplitude. This is a condition that allows realization of large arrays of receivers without extensive LO operation power.
• Figs. 2 and 3 show one detailed embodiment, where fig. 2 shows the layout of the embodiment in so-called micro-strip technique and fig. 3 is the circuit diagram.
• the mixer i.e. the transistor 20, according to this embodiment is of so-called "gate mixer” type and comprises of the terminals source 21, gate 22 and drain 23.
• the antenna 24, in this case, is a so-called patch antenna, in which one of polarization 25 is used to couple LO and the other one 26 to couple RF (signal).
• LO and RF are connected to the gate electrode 22.
• the mixing process is obtained because the relationship between the gate voltage and the output signal (23) is non-linear.
• the gate electrode is fed with voltage N gs via a low-pass filter comprising R réelle C, and L,.
• the drain electrode 23 is fed via a low-pass filter consisting of R 2 , C 2 , and L2.
• a stub 27 is connected to drain which short-circuits between RF and LO so that the intermediate frequency IF can be outputted through the terminal 28.
• N gs and V ⁇ are so adjusted that an optimal performance is achieved.
• LO and RF have different polarizations. Different polarizations can be produced by using a polarizer, which combines LO and RF and at output they become in different polarizations with very small losses. This means that the amplifying can be obtained for both RF and LO.
• the antenna can be tailored for RF and LO frequencies, respectively, by varying the side length of the patch, i.e. the patch antenna may have rectangular geometry. If the frequencies are close to each other (within the resonance frequencies) it is also possible to supply the LO and RF in the same polarization. In that case only one connection to the antenna is needed instead of two, which is shown in figs. 2 or 3.
• the requirements on LO are reduced. This is very important in high-frequency applications. Through the gate mixer low losses are obtained. Moreover, no losses between antenna and transistor are obtained. In the gate mixer it is very important to apply both the LO and signal with so little loss as possible, otherwise the performance is deteriorated, either through the sensitivity deterioration or increased LO requirements. In a conventional gate mixer, the LO is applied with directional coupler or ring filter, but these couplers have losses between 3 and 10 dB. Because of these losses, the decreasing potential of the LO power will be wasted.
• the embodiment shows one of many possible antenna configurations.
• the receiver element can also be designed in multilayer, strip-line, slot-line, co-planar waveguide technique or a combination of the same.
• the antenna element can be of patch, slot, horn type or a combination of these.
• the transistor can be coupled either in "grounded-gate mode" or "active mode".
• LO 25 and RF 26 are applied in different polarizations and no interferences appear.
• the stub 27, which is an open circuit, is used to allow the mixer operate correct ly.
• R2 and R3 are used to supply the DC current of the device and to decouple. Moreover, these allow extraction without losses in IF at IF 0Ut 28 from the drain
• Fig. 4 shows the layout of a 4 x 4 matrix including 16 elements according to fig. 2.
• the device is intended to function at approximately 10 GHZ, but 8 x 8 or larger matrices for operation areas from about 10 to 100 GHZ are also possible.
• the invention allows a very compact construction, which is well adapted for integrated image generating radar and radiometers, which can be used for instance in multistatisc radars, where the transmitter and receiver are separated in space.
• the image generating radar can be used for safer identification of radar echoes and as navigation aid in aircrafts or other vehicles at fog or smoke.
• the image generating radiometers can for instance be used to detect oil spillage or the like through ai ⁇ lane monitoring, detect oil spillage from ships or via aircraft or detect objects which otherwise are invisible for the radar, such as vehicles based on "stealth technique".
• An array of sensors according to the invention can for example be used to focus a lens or a parabolic antenna in a "staring" array configuration.

Landscapes

• Engineering & Computer Science (AREA)
• Radar, Positioning & Navigation (AREA)
• Remote Sensing (AREA)
• Computer Networks & Wireless Communication (AREA)
• Signal Processing (AREA)
• Input Circuits Of Receivers And Coupling Of Receivers And Audio Equipment (AREA)
• Variable-Direction Aerials And Aerial Arrays (AREA)

Applications Claiming Priority (3)

Publications (1)

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ID=20409227

Family Applications (1)

Country Status (6)

Families Citing this family (2)

Family Cites Families (1)

• 1997
  • 1997-12-01 SE SE9704483A patent/SE511979C2/sv not_active IP Right Cessation
• 1998
  • 1998-12-01 AU AU17924/99A patent/AU1792499A/en not_active Abandoned
  • 1998-12-01 JP JP2000539545A patent/JP2002509372A/ja active Pending
  • 1998-12-01 WO PCT/SE1998/002204 patent/WO1999031755A2/en not_active Ceased
  • 1998-12-01 IL IL13645298A patent/IL136452A0/xx unknown
  • 1998-12-01 EP EP98962763A patent/EP1036423A2/de not_active Withdrawn

Non-Patent Citations (1)

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