Home > Reviews > Beamwidths antenna amplifier

Beamwidths antenna amplifier

We propose a simple solution for jamming mitigation of L1 band GPS by electronically switching antenna beam for wide and narrow beamwidths. Assuming the jamming signal is directed from low elevation angles, antenna reception can be made significantly lower at these angles by electronically reconfiguring the antenna beamwidth. Four-element antenna array and one of the elements of the array are designated as antijam array mode and normal mode of the antenna. The antenna is placed on a degenerate-ground with symmetric slots in the ground.


We are searching data for your request:

Schemes, reference books, datasheets:
Price lists, prices:
Discussions, articles, manuals:
Wait the end of the search in all databases.
Upon completion, a link will appear to access the found materials.
Content:
WATCH RELATED VIDEO: INSTALL CAR RADIO FM AMPLIFIER (ANTENNA BOOSTER)

US3771163A - Electronically variable beamwidth antenna - Google Patents


Means for obtaining an approximate change in beamwidth electronically in an antenna system comprised of a linear array of elements. Means are coupled to one of two traveling wave tubes TWT which feed the array for selectively serrodyning the signal fed to said one TWT, resulting in a frequency shift of the signal feeding one half of the array with respect to the signal feeding the other half.

With the serrodyning means deactivated, all of the antenna elements are fed in-phase rf signals and a conventional linear array results providing a narrow beamwidth along the electrical boresight of the array. With the serrodyning means activated and since beamwidth is inversely proportional to aperture size, each half of the antenna array is fed by separate respective coherent signals whereupon two independent beams illuminating the same angular sector will be formed having a beamwidth approximately twice that of the whole non-serrodyned array.

Marinaecio, Crofton,. Henson et al. With the serrodyning means deactivated, all of the antenna elements are fed inphase rf signals and a conventional linear array results providing a narrow beamwidth along the electrical boresight of the array.

With the serrodyning means activated and since beamwidth is inversely proportional to aperture size, each half of the: antenna array is fed by separate respective coherent signals whereupon two independent beams illuminating the same angular sector will be formed having a beamwidth approximately twice that of the whole non-serrodyned array. Field of the Invention This invention relates generally to variable beamwidth antennas and more particularly to an antenna system for airborne use having electronic control.

Some radar and ECM systems require narrow elevation beamwidth for low altitude flightin order to concentrate the available power in the region of interest as well as providing a relatively small amount of main beam down-tilt while for high altitude flight a broad elevation beamwidth and a greater down-tilt is desired.

Description of the Prior Art In microwave antenna systems it may be desired to vary the width of the radiated beam in a predetermined manner. Widening of the beamwidth can be accomplished, for example, by defocusing the antenna such as disclosed in US. In accordance with the invention disclosed therein, a variable beamwidth antenna for use in a system which derives information depending on phase relationships existing between different portions of the received signal and comprises: an antenna, first means for changing the focusing effect provided by the antenna, and second means coupled to the first means for providing phase shift compensation related to the change in focusing effect produced by the first means.

Widening the beamwidth of an antenna can also be accomplished by reducing the effective diameter of the radiating aperture; however, such methods heretofore have been usually inefficient and complicated and subject to various defects related to operation with reduced aperture. Additionally, beam shaping can also be accomplished by the method of sidelobe suppression, such as taught in US.

A common rf signal source is coupled to both rf amplifiers and in a first mode of operation, all n elements are fed in-phase to provide a beam of relatively narrow beamwidth along the array boresight. In the configuration shown in FIG. An rf amplifier 22 of microwave signals, such as a traveling wave tube TWT , is coupled to the power splitter 16 by means of the feeder element TWT amplifier 22 has its input coupled back to a primary power splitter 26 by means of feeder element The power splitter 26 is coupled to an initial TWT amplifier by means of feeder element The input of TWT amplifier 28 is coupled to suitable rf input means 32 by means of feeder element The other half of the array which comprise elements 14 and 14 are coupled to the primary power splitter 26 in a manner similar to the elements 12 and I2 described above.

More particularly, radiating elements 14 and 14 are coupled by means of respective feeder elements 36 and 38 to a power splitter 40 which has its input connected to the output of TWT amplifier 42 by means of feeder element The input to TWT amplifier 42 is coupled back to the power splitter 26 by means of feeder element TWT amplifier 42 additional ly is adapted to be controlled by means of a serrodyne signal generator 48 by means of the electrical signal circuit connection The serrodyne signal generator 48, moreover, is adapted to be coupled toa control terminal 52 whic is adapted to receive either an ON or OFF control signal which causes the signal generator 48 to respectively generate or not generate" a repetitive sawtooth waveform which is coupled to the circuit lead 50 for modulating the TWT amplifier When an ON signal is applied to terminal 52, a sawtooth waveform will be produced by the signal generator 48 which is coupled by means of circuit lead 50 to the TWT for serrodyning the :rf energy fed to TWT 42 from the power splitter The rf energy in the TWT 42 is serrodyne modulated by the sawtooth output from serrodyne signal generator Serrodyne modulation results in a continuous linear phase shift repeated every ' radians.

Such a phase shift causes the energy in the original carrier frequency to be displaced or shifted by a predetermined constant amount equal to the frequency of the modulating signal, that is, the frequency of the sawtooth waveform appearing on circuit lead 50 when an ON signal is applied to terminal When an OFF signal appears at terminal 52, signal generator 48 is deactivated and the serrodyne modulating signal is removed from TWT The concept of serrodyne modulation is further explained in US.

OHara, et al. Bearing the foregoing in mind, in the normal or first mode of operation, the serrodyne modulating sawtooth waveform is absent due to the application of an OFF control signal to terminal 52 coupled to serrodyne signal generator The rf input signal to be radiated is applied to input means 32 where it is fed through TWT amplifier 28 to the primary power splitter The rf signal is then fed into two separate channels which include TWT amplifiers 22 and 42, respectively.

The rf ouput appearing in feeder arms 24 and 44 are in-phase whereupon it is respectively fed to power splitters 16 and Antenna elements 12 and 12 are fed in-phase rf signals from the power splitter 16 while antenna elements 14 and 14 are fed the same in-phase rf signals from power splitter Thus a linear array comprised of n 4 elements radiate a relatively narrow beam alongthe boresight axis having a virtual source designated by reference numeral 52 as shown in FIG.

Since the beamwidth is inversely proportional to the diameter of the radiating aperture wherein the aperture of the array comprises the number of elements times the aperture for a single element, the beam is narrower than if a smaller number than n elements comprise the array. The second mode of operation is directed to radiatin'ga relatively wider beamwidth and to this end an ON control signal is now applied to terminal 52 whereupon the signal generator 48 couples a repetitive sawtooth waveform to the TWT The rf signal to be radiated is again fed from the primary power splitter 26 and from there to the TWT amplifier 22 and to the TWT amplifier TWT 42 is now serrodyned modulated by the sawtooth waveform applied thereto from the signal generator As noted above, serrodyne modulation causes a frequency shift of the rf signal.

The resulting effect is the formation of two separate beams A and B illuminating the same angular sector, beam A from the upper sub-array and one from the lower sub-array.

At operational distances, however, wide beams A and B overlap and appear to emanate from the same virtual source 52 as the narrow beam as shown in FIG. Thus control of the beamwidth is obtained by turning the serrodyne modulated signal on and off, that is ON for the broadbeam and OFF for the narrow beam. The subject invention has particular application for airborne ECM systems where the TWT amplifiers 22 and 42 receive signal common sinal which can be either a noise signal or a received radar signal which is to be reradiated repeater operation.

The line lengths and TWT phase shifts are normally matched so that all antenna elements will be fed in-phase in the narrowband mode and a conventional linear array will result providing a narrow beamwidth with the electrical boresight of the array corresponding to the mechanical boresight of the array. The wider beamwidth is provided in the second mode of operation by serrodyning TWT amplifier 42, resulting in a frequency shift of the signal feeding one half of the array with respect to the signal feeding the other half.

Since in the second mode of operation two beams are formed, the resulting composite pattern will have the average power equal to the sum of that from each beam. The composite signal will also be amplitude modulated at a rate corresponding to the serrodyne rate, however, if the rate is high compared to the intended jamming modulation, no significant degradation will result.

The net result is therefore an in-flight electronic beamwidth control. Having disclosed what is at present considered to be the preferred embodiment of the subject invention,. A variable beamwidth antenna fed from a source of rf signals, comprising in combination:.

The antenna as defined by claim 1 wherein said antenna array comprisesa linear microwave array. The antenna as defined by claim 2 wherein said second feeder circuit includes an RF amplifier. The antenna as defined by claim 3 wherein said RF amplifier comprises a traveling wave tube. The antenna as defined by claim 4 and additionally including a traveling wave tube in said first feeder circuit. The antenna as defined by claim 1 wherein said serrodyne circuit means includes a sawtooth waveform signal generator selectively rendered operative in said one mode of operation, and inoperative in said another mode of operation.

The antenna as defined by claim ll wherein said input means includes a first RF power splitter coupled from said source of rf signals to said first and second feeder circuit, and. The antenna as defined by claim 7 wherein said input means additionally includes an rf amplifier coupling said source of rf signals to said first rf power splitter. The antenna as defined by claim 8 wherein said antenna array comprises a linear microwave array and said rf amplifier comprises a traveling wave tube, and.

The antenna as defined by claim 1 wherein said first and second feeder circuit include feeder elements having line lengths which are substantially equal for providing rf signals which are in phase at said n elements during said another mode of operation.

The antenna as defined by claim 1 wherein said antenna array comprises a linear microwave array. The antenna as defined by claim 8 wherein said antenna array comprises a linear microwave array and said rf amplifier comprises a traveling wave tube, and additionally including a traveling wave tube respectively in said first and secoNd feeder circuit.

USA true USA en. JPSA en. DEA1 en. FRB1 en. System for scheduling reverse-channel messages in narrowband communications systems and methods of operation. System and method of operation an array antenna in a distributed wireless communication network.

System and method of operation of an array antenna in a distributed wireless communication network. Overlapped subarray antenna feed network for wireless communication system phased array antenna. USB1 en. FRA1 en. Multimode antenna feed system having a plurality of tracking elements mounted symmetrically about the inner walls and at the aperture end of a scalar horn. Demmerle et al. JPB2 en.

Sidelobe suppressing antenna system comprising directional coupler and phase controlmeans for beam shaping. USB2 en. Phased array antennas using frequency multiplication for reduced numbers of phase shifters. GBA en.


Beamwidth And Directivity Of Antenna

Beamwidth And Directivity Of Antenna. Hadi Kerrouchi Aug 9, , AM Aug 9. Reply to author. Report message as abuse.

To verify the proposed antenna with the axial ratio controller, the wideband CP antenna is implemented at GHz. A low noise amplifier.

The Importance of Antenna Beamwidth in RF Testing


The half-power point or half-power bandwidth is the point at which the output power has dropped to half of its peak value; that is, at a level of approximately -3 dB. In the characterization of antennas the half-power point relates to measurement position as an angle and describes directionality. The bandwidth of a filter or amplifier is usually defined as the difference between the lower and upper half-power points. This is, therefore, also known as the 3 dB bandwidth. There is no lower half-power point for a low-pass amplifier, so the bandwidth is measured relative to DC , i. In antennas, the expression half-power point does not relate to frequency: instead, it describes the extent in space of an antenna beam. The half-power point is the angle off boresight at which the antenna gain first falls to half power approximately -3 dB [a] from the peak. The angle between the -3 dB points is known as the beamwidth. From Wikipedia, the free encyclopedia. Retrieved 5 August

Importance of Antenna Selection

beamwidths antenna amplifier

Antenna beamwidth determines the expected signal strength given the direction and radiation distance of an antenna. The beamwidth will vary given a number of different factors such as the antenna type, design, orientation and radio frequency. Understanding beamwidth and how it influences a test environment is critical to accurate and repeatable tests. How beamwidth is measured To calculate an antenna beamwidth, it is first important to understand directional antennas and antenna gain. Gain is more than increased signal strength.

PWS designs and manufactures a number of different products used to enhance a wireless audio rental system. These range from Helical antennas to transmit combiners, all used and requested by many production houses across the country.

Half-power point


For electrically large antennas, the half-power beamwidths are small whereas for electrically small antennas, the half-power beamwidths large. Start Learning English Hindi. This question was previously asked in. Attempt Online. Answer Detailed Solution Below Option 4 : 8. Start Now.

What is Half Power Beam Width (HPBW)?

Antenna gain is a performance indicator gauged in comparison to a reference source. This article explains antenna gain and dispels some of the misconceptions surrounding this valuable metric. It also discusses the gain typical of common antenna types and provides tools to calculate vital parameters relevant to antenna gain. How Does Antenna Gain Work? First, it warrants mention that in some industries — such as broadcast engineering — manufacturers may utilize dBd gain relative to a dipole antenna as a metric, rather than dBi. Note that dBd is inherently greater, defined as 2.

The point is that antenna coverage patterns and (if specified) beam widths should be considered when setting up a system to ensure the antenna.

PWS Products for Rent

Supporting notes on the webinar can be found on the AH Systems website. In the last entry we introduced a method that provides superior visualization of the system behavior. We continue on this theme by factoring in beamwidth loss.

Understanding Antenna Gain, Beamwidth, And Directivity

RELATED VIDEO: TV Antenna Signal Amplifiers Explained: Do They Improve Reception?

Skip to Main Content. A not-for-profit organization, IEEE is the world's largest technical professional organization dedicated to advancing technology for the benefit of humanity. Use of this web site signifies your agreement to the terms and conditions. Wideband Circularly Polarized Antenna With Reconfigurable 2-Dimensional Axial Ratio Beamwidth Abstract: This paper proposes a wideband circularly polarized antenna with a reconfigurable 2-dimensional axial ratio. For mobile satellite communication, the low profile CP antenna with wide axial ratio scanning and a wide frequency bandwidth is essential. In this paper, we propose the wideband CP antenna with an axial ratio controller.

Means for obtaining an approximate change in beamwidth electronically in an antenna system comprised of a linear array of elements. Means are coupled to one of two traveling wave tubes TWT which feed the array for selectively serrodyning the signal fed to said one TWT, resulting in a frequency shift of the signal feeding one half of the array with respect to the signal feeding the other half.

Beamwidth Loss and Why Test Staff and dB Notation should be Friends

With four high band ports covering MHz and two low band ports covering MHz, this four foot 1. The HexPort allows separate tilt control for each pair of ports enabling maximum flexibility in network deployment. CCI has engineered its antennas using new and innovative design techniques to provide optimal sidelobe performance, sharp elevation beams, and high front to back ratio. Multiple technologies can now be connected to a single antenna, reducing tower load, lease expense, deployment time and installation cost. CCI antennas are designed and produced to ISO certification standards for reliability and quality in our state-of-the-art manufacturing facilities. South Hackensack, NJ Multi-Port Antennas.

Reconfigurable Antenna for Jamming Mitigation of Legacy GPS Receivers

Half Power Beam Width or HPBW is an angular width in degrees , measured on the major lobe of an antenna radiation pattern at half-power points i. The 3 dB points on the major lobe of the antenna are the half power points. These points are at -3 dB from where the point of maximum amplitude. We know, the energy radiated by an antenna is characterized by its Radiation pattern.




Comments: 3
Thanks! Your comment will appear after verification.
Add a comment

  1. Melkree

    Granted, this is a funny answer

  2. Jeric

    I am sorry, this variant does not approach me. Who else, what can prompt?

  3. Broderic

    In my opinion you are not right. I am assured. I can defend the position. Write to me in PM, we will talk.