CA1179055A - Electronically scanned antenna system having a linear array of endfire elements - Google Patents
Electronically scanned antenna system having a linear array of endfire elementsInfo
- Publication number
- CA1179055A CA1179055A CA000399442A CA399442A CA1179055A CA 1179055 A CA1179055 A CA 1179055A CA 000399442 A CA000399442 A CA 000399442A CA 399442 A CA399442 A CA 399442A CA 1179055 A CA1179055 A CA 1179055A
- Authority
- CA
- Canada
- Prior art keywords
- antenna
- endfire
- elements
- yagi
- plane
- 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.)
- Expired
Links
Landscapes
- Aerials With Secondary Devices (AREA)
- Variable-Direction Aerials And Aerial Arrays (AREA)
Abstract
UNITED STATES PATENT APPLICATION
OF
FREDERICK M. GANZ, JUSTINE D. CERMIGNANI, AND RICHARD H. INGRAM
FOR
AN ELECTRONICALLY SCANNED ANTENNA SYSTEM
HAVING A LINEAR ARRAY OF ENDFIRE ELEMENTS
Abstract Of The Disclosure An electronically scanned antenna system having a linear array of endfire elements. The endfire elements are laterally spaced between about 0.3 ? to 0.9 ? apart, preferably about 0.55 ? apart, to enhance the effects of mutual coupling therebetween for broadening the radiation signal pattern of the elements in the plane of the array. Advantageously, the endfire elements may be of the Yagi type with each endfire element including a common reflector, a driver, and a plurality of directors.
OF
FREDERICK M. GANZ, JUSTINE D. CERMIGNANI, AND RICHARD H. INGRAM
FOR
AN ELECTRONICALLY SCANNED ANTENNA SYSTEM
HAVING A LINEAR ARRAY OF ENDFIRE ELEMENTS
Abstract Of The Disclosure An electronically scanned antenna system having a linear array of endfire elements. The endfire elements are laterally spaced between about 0.3 ? to 0.9 ? apart, preferably about 0.55 ? apart, to enhance the effects of mutual coupling therebetween for broadening the radiation signal pattern of the elements in the plane of the array. Advantageously, the endfire elements may be of the Yagi type with each endfire element including a common reflector, a driver, and a plurality of directors.
Description
9U~5 1 The present invention relates to antennas, and more
2 particularly to an electronically sc~nned antenna sys~em
3 havlng a linear array of endfire elements. An endfire
4 elenent is deCi~ed as an elemer whose maximum ~ain is obtained along the element axis.
S Electronically scanned lil1ear arrays of simple - elements are well known. Such arrays are generally 8 character zed by relatively low gain, and a broad 9 elevation patter~. Arrays of endfire elements in which scanning is accomplished mechanically by rotating the 11 entlre ar ay are also known. These arrays are unsatisfactory 12 when conform~l mounting in the plane of the array is required, 13 e.g., on or within airfoil surfaces (wings and horizontal 14 stabilizer) of an aircraft.
Various antenna element configurations are known.
16 United States Patent 2,236,333 (Beck et al.) discloses a 17 broad bandwlth endfire antenna. United States Patent 18 3,182,330 (Blume) discloses an antenna array having non-19 unirorm spacing of the individual elements. United States Patent 2,425,887 (Lindenblad) discloses an endfire antel1na 21 in which all t~e elements are energized with equal voltages 22 in proper ph2se. United States Patent 3,258,774 (Kinsey) 23` discloses a series-fed phased antenna array. See also 24 United States Patent 3,509,577 (Kinsey). United-States Patent 2,4l9,502 (Kandoian) discloses a binomial array 26 for producing a clover leaf pattern having highly directive 27 properties. A conventlonal Yagi antenna is referenced ~ . . ~
~79~S~i in United States Patent 3,466,655 (Mayes et al.).
Moreover, generally in known antenna array constructions mu-tual coupling is regarded as detrimental and means are taken to minimize its effect. In contrast the present invention utilizes mutual coupling to enhance antenna performance.
Endfire elements are known to produce high density with narrow patterns in both planes (azimuth and elevation), and are therefore, according to conventional practice, considered unsuitable forwide angle electronic scanning when multiple elements are arrayed. (The scan angle limits being established by the width of the in-array element pattern.) In contrast with conventional practice, the present invention advantageously utilizes arrayed multiple elements for wide angle scanning by employing mutual coupling between the elements to broaden the endfire element pattern in the plane in which electronic scanning is desiredO
The present invention provides an antenna having a linear array of endfire elements, comprising: a plurality of laterally spaced endfire elements, said endfire elements being spaced from about 0.3 A to 0.9 ~ apart to enhance the effects of mutual coupling therebetween to broaden the element pattern in the plane of the array.
From another aspect, the present invention provides an antenna system for conformal mounting on an aircraft for generating an electronically scanned main radiation lobe comprising: (a) a linear array of Yagi antennas which are laterally spaced from one another a distance of about 0.3 A to 0.9 A center to center, each of said Yagi antennas including a driven element, a reflector member and a director member, each of which having a length less than the spacing between each adjacent Yagi antenna, each of said Yagi antennas being operative to radiate: (i) free space beam widths Bx and By in the coordinate X and Y planes, respectively, the values of Bx and By being substantially less than 90 ; and (ii) free space maximum gain in the direction of the lengths of said Yagi antennas; and (b) means for scanning the antenna sys-tem mai.n lobe in the X plane ovèr an angle A substantially greater than Bx, while at the same time maintaining a system main lobe beam width in the Y plane which approximates By, said scan angle A
being able to be broadened to greater than 90 as a result of enhanced mutual coupling between said Yagi antennas.
~79(~5~
, "Electronic scanniny" as the term is used herein entails adjustments in the excita-tion coefficients (e.g., phase and amplitude) of the elements in the array in accordance with the direction in which the formation of a beam is desired.
It is well known to those skilled in the art that the beam of an antenna points in a direction tha-t is normal to the phase front. In phased arrays the phase front is adjusted to steer the beam by individual control of the phase excitation of each radiating element. Phase shifters are electronically actuated to permit rapid scanning and are adjusted in phase to a value between 0 and 2 ~ radians. While this method of electronic scanning is perhaps the most commonly used, other means may be employed to effect the same changes in the phase front of the array to produce steerage of the beam.
Control of the excitation coefficients of the` elements of the array is commonly known as "antenna feed", and includes all means for independently or dependently controlling the amplitude and phase of the signals to or from the indivudual elements of the antenna array, and dividing or combining means therefore.
~7~3~55 1 The present invention is ~llustrated ln the 2 accompanying drawings, in which: -3 FI~JRE 1 is a top plan view of a linear array of endfire elements according to the present invention;
FIGURE 2 is a perspective view of a Yagi S endfire element for the llnear array of the present 7 invention;
8 FIGURE 3 is a top plan of a linear array of 9 Yagi endfire elements of the type shown in Fig. 2 in which all the endfire elements have a co~non reflector;
11 FIGURE 4 is a top plan vlew of a linear array 12 of endfire elements similar to Fig. 3 being scanned at 13 an angle ~ ; and 14 FIGURE 5 is a perspective view of an aircraft with parts broken away to indicate the mounting thereon 16 of linear arrays of endfire elements in accordance with 17 the present invention.
18 Referring to Fig. 1, an antenna according to the 19 present invention is generally illustrated at 10. It should be understooc that the antenna 10 may be used with 21 acoustlc as well as electromagnetic waves, although in the 22 description the antenna will be described with reference to 23 electromagnetic waves. The antenna 10 includes a linear 24 array of endfire elements 12 electronically coupled to an element driving network 14 which is conventlonally 26 known as an antenna feed.
11'79Q5S
1 Each endfire element 12 is laterally spaced a 2 distance (D) between abou~ 0.3 ~ and about 0.9 h apart~
preferably about 0.55 ~ apart (center-to-center) to 4 enhance the effects of mut~al coupling between the elements 12, resulting in a broadened element pattern of the mainbeam in the plane of the array, see the dotted lines and arrows 7 in Fig. 1. The length (L) of each individual element 12 8 is approximately 1.25 ~ .
9 Referring to Fig. 2, a Yagi endfire element 12A
for use in the array of the present invention is shown. As 11 is well known, a Yagi endfire arLay includes at least two 12 parasitic elements in addit;on to the driven element. The 13 Yagi endfire element 12A includes six conductive elements 16, -14 18, 20, 22~ 24 and 26. Such a multiparasitic array is known 1~ as a 6-element beam. Each element has a diameter of 16 approximately 0.01 ~ and a length of approximately 0.5 ~ .
17 The six elements 16, 18, 20, 22, 24 and 26 are 18 positioned in spaced parallel relationship along the same 19 line of sight (transverse axis) with the spacing between adjacent elements being approximately .25 ~ . The six 21 elements lG, 18, 20, 22, 24, and 26 are supported on a pair 12 of non-conductive Plexiglas- suppcrts 28 and 30, e.g., by 23 inserting the elements 16~ 18, 20, 22, 24, and 26 into 24 mating holes in the Plexiglass suport. The supports 28 and 30 electrically insulate the elements 16, 18, 20, 22, 24 and 26 26 from one anotner, and advantageously are substantially 27 invisible to the resulting electromagnetic wavesf ~ f ~ s /~a~ f~ rk .
-~7~ ~5 S
1 Element 16 is the reflector element, element 18 the 2 driven element, and elements 20, 22, 24 and 26 the director 3 elements. A coa~ial cable 32 is electrically coupled to 4 the driven element 18 for providing a signal thereto.
The reflector 16 and directors 20-26 interact in a conventional S manner to provide increased gain and unidirectivity to the 7 radiated signal pattern. The free-space half-~ower beam-8 widths of element 12A is 42 in the E plane and 48 in the 9 H plane.
Referring to Flg. 3, ten endfire elements 12A-J
11 of the type shown in Fig. 2 are arranged in a linear array 12 lOA. The endfire elements 12A-J have a common reflector 13 16A and are closely spaced laterally a distance of between 14 about 0.3 ~ and about 0.9 ~ apart, preferably about 0.55 ~ apart (center-to-center), to increase thè effects 16 of mutual~coupling therebetween~ With such an arrangement, 17 the in-array pattern, i.e., the angle over whlch the antenna 18 mainlobe can be electronically-scanned increases from 42 19 for the single endfire element 12A of Fig. 2, see the dotted lines and arrows of Fig, 2, to greater than 90 in the 21 array lOA. The narrow H plane pattern of 48 for the 22 single endfire element 12A is maintained in the array lOA~
23 Thus, the effect of closely spacing the endfire elements 12A
24 in the linear array 10 is to broaden the element pattern in the plane of the array lOA (E plane) while preserving the narrow 26 H plane pattern.
~- ~
~ .7~3()SS
., 1 The broadened E-plane pattern o the in-array 2 endfire element may be demonstrated as follows: The elements 3 12A-D and 12F-J have individual terminating impedances 34A-D
4 and 34F-J coupled to ground 36 in the array lOA. The terminating impedances 34A-D and 34F-J are chosen to match S the antenna driving point impedance to an antenna scan angle 7 o~ 0 in the E-plane. In ~he embodiment illustrated in Fig. 3, 8 the terminating impedances 34A-D and 34F-J are 50 ohms.
9 Element 12E is monitored by meter 38 which measures the power received by element 12E when ~he array lOA is used as a 11 receiving device to receive signals transmitted by a 12 radiating device (not shown) positioned at sufficient 13 distance fro~ the array lOA so as to be in the far field 14 of the array lOA. As the array lOA is rotated in angle with respect to the radiating device, the power measured 16 in meter ~8 will vary in proportion to the in-array element l? pattern of element 12E. This method of pattern measurement 18 is well known in the art. Moreover, it is also well known 19 in the art that the in-array element pattern measured in this manner is approximately proportional to the gain of 21 the array lOA as a function of angle when the outputs 22 o all of the elements L2A-J are utilized to io m a beam.
_ g _ ~1'7911~55 ., 1 Wlth reference to Fig. 4, the array lOA operates 2 as follows: A feed means (not shown) applies transmission 3 signals to a combining/dividing network 40 which splits 4 the signals for transmission by the individual elements 42 of the array 44 (N elements are shown). N phase shifters 46 shift the phase of the signals in accordance with the 7 direction in which a beam is desired. In applications where une~ual amplitudes are desired for each antenna 9 element to provide lower antenna sidelobes (co~monly known as amplitude taper), the combining/dividing network 48 11 advantageously provides such a distribution.
12 The antenna array lOA with its feed is linear 13 passive and ~ilateral and is subject to the law of 14 reciprocity so that when it is used in the receiving mode its characteristics are unaltered.
16 Referring to Fig, 5, an aircraft 48 is illustrated 17 with antenna arrays 10 B, C and D in accordance with the 18 present invention positioned in the wing leading edges 19 50 and 52 and in the horizontal stabilizer 54. With this arrangement 360 azimuthal coverage ls obtained by 21 electronically scanning the arrays lOB-D and conventional 22 side-looking antennas 56 and 58 mounted on opposite sides 23 of the ~uselage 60. Advantageously, such an arrangement t4 avoids the need for a large dome mounted on the fuselage 60 which must be mechanically rotated to provide the same 26 360 azimuthal coverage.
~l1'7~)055 1 It should be apparent to those skilled in the 2 art that various modifications may be made in the present 3 invention without departing from the spirit and scope 4 thereof, as described in the specification and defined 6 ln t appended claims.
9 .
13 . ~ .
18 .
~0 24 .
__ __ _, _ _ __ __
S Electronically scanned lil1ear arrays of simple - elements are well known. Such arrays are generally 8 character zed by relatively low gain, and a broad 9 elevation patter~. Arrays of endfire elements in which scanning is accomplished mechanically by rotating the 11 entlre ar ay are also known. These arrays are unsatisfactory 12 when conform~l mounting in the plane of the array is required, 13 e.g., on or within airfoil surfaces (wings and horizontal 14 stabilizer) of an aircraft.
Various antenna element configurations are known.
16 United States Patent 2,236,333 (Beck et al.) discloses a 17 broad bandwlth endfire antenna. United States Patent 18 3,182,330 (Blume) discloses an antenna array having non-19 unirorm spacing of the individual elements. United States Patent 2,425,887 (Lindenblad) discloses an endfire antel1na 21 in which all t~e elements are energized with equal voltages 22 in proper ph2se. United States Patent 3,258,774 (Kinsey) 23` discloses a series-fed phased antenna array. See also 24 United States Patent 3,509,577 (Kinsey). United-States Patent 2,4l9,502 (Kandoian) discloses a binomial array 26 for producing a clover leaf pattern having highly directive 27 properties. A conventlonal Yagi antenna is referenced ~ . . ~
~79~S~i in United States Patent 3,466,655 (Mayes et al.).
Moreover, generally in known antenna array constructions mu-tual coupling is regarded as detrimental and means are taken to minimize its effect. In contrast the present invention utilizes mutual coupling to enhance antenna performance.
Endfire elements are known to produce high density with narrow patterns in both planes (azimuth and elevation), and are therefore, according to conventional practice, considered unsuitable forwide angle electronic scanning when multiple elements are arrayed. (The scan angle limits being established by the width of the in-array element pattern.) In contrast with conventional practice, the present invention advantageously utilizes arrayed multiple elements for wide angle scanning by employing mutual coupling between the elements to broaden the endfire element pattern in the plane in which electronic scanning is desiredO
The present invention provides an antenna having a linear array of endfire elements, comprising: a plurality of laterally spaced endfire elements, said endfire elements being spaced from about 0.3 A to 0.9 ~ apart to enhance the effects of mutual coupling therebetween to broaden the element pattern in the plane of the array.
From another aspect, the present invention provides an antenna system for conformal mounting on an aircraft for generating an electronically scanned main radiation lobe comprising: (a) a linear array of Yagi antennas which are laterally spaced from one another a distance of about 0.3 A to 0.9 A center to center, each of said Yagi antennas including a driven element, a reflector member and a director member, each of which having a length less than the spacing between each adjacent Yagi antenna, each of said Yagi antennas being operative to radiate: (i) free space beam widths Bx and By in the coordinate X and Y planes, respectively, the values of Bx and By being substantially less than 90 ; and (ii) free space maximum gain in the direction of the lengths of said Yagi antennas; and (b) means for scanning the antenna sys-tem mai.n lobe in the X plane ovèr an angle A substantially greater than Bx, while at the same time maintaining a system main lobe beam width in the Y plane which approximates By, said scan angle A
being able to be broadened to greater than 90 as a result of enhanced mutual coupling between said Yagi antennas.
~79(~5~
, "Electronic scanniny" as the term is used herein entails adjustments in the excita-tion coefficients (e.g., phase and amplitude) of the elements in the array in accordance with the direction in which the formation of a beam is desired.
It is well known to those skilled in the art that the beam of an antenna points in a direction tha-t is normal to the phase front. In phased arrays the phase front is adjusted to steer the beam by individual control of the phase excitation of each radiating element. Phase shifters are electronically actuated to permit rapid scanning and are adjusted in phase to a value between 0 and 2 ~ radians. While this method of electronic scanning is perhaps the most commonly used, other means may be employed to effect the same changes in the phase front of the array to produce steerage of the beam.
Control of the excitation coefficients of the` elements of the array is commonly known as "antenna feed", and includes all means for independently or dependently controlling the amplitude and phase of the signals to or from the indivudual elements of the antenna array, and dividing or combining means therefore.
~7~3~55 1 The present invention is ~llustrated ln the 2 accompanying drawings, in which: -3 FI~JRE 1 is a top plan view of a linear array of endfire elements according to the present invention;
FIGURE 2 is a perspective view of a Yagi S endfire element for the llnear array of the present 7 invention;
8 FIGURE 3 is a top plan of a linear array of 9 Yagi endfire elements of the type shown in Fig. 2 in which all the endfire elements have a co~non reflector;
11 FIGURE 4 is a top plan vlew of a linear array 12 of endfire elements similar to Fig. 3 being scanned at 13 an angle ~ ; and 14 FIGURE 5 is a perspective view of an aircraft with parts broken away to indicate the mounting thereon 16 of linear arrays of endfire elements in accordance with 17 the present invention.
18 Referring to Fig. 1, an antenna according to the 19 present invention is generally illustrated at 10. It should be understooc that the antenna 10 may be used with 21 acoustlc as well as electromagnetic waves, although in the 22 description the antenna will be described with reference to 23 electromagnetic waves. The antenna 10 includes a linear 24 array of endfire elements 12 electronically coupled to an element driving network 14 which is conventlonally 26 known as an antenna feed.
11'79Q5S
1 Each endfire element 12 is laterally spaced a 2 distance (D) between abou~ 0.3 ~ and about 0.9 h apart~
preferably about 0.55 ~ apart (center-to-center) to 4 enhance the effects of mut~al coupling between the elements 12, resulting in a broadened element pattern of the mainbeam in the plane of the array, see the dotted lines and arrows 7 in Fig. 1. The length (L) of each individual element 12 8 is approximately 1.25 ~ .
9 Referring to Fig. 2, a Yagi endfire element 12A
for use in the array of the present invention is shown. As 11 is well known, a Yagi endfire arLay includes at least two 12 parasitic elements in addit;on to the driven element. The 13 Yagi endfire element 12A includes six conductive elements 16, -14 18, 20, 22~ 24 and 26. Such a multiparasitic array is known 1~ as a 6-element beam. Each element has a diameter of 16 approximately 0.01 ~ and a length of approximately 0.5 ~ .
17 The six elements 16, 18, 20, 22, 24 and 26 are 18 positioned in spaced parallel relationship along the same 19 line of sight (transverse axis) with the spacing between adjacent elements being approximately .25 ~ . The six 21 elements lG, 18, 20, 22, 24, and 26 are supported on a pair 12 of non-conductive Plexiglas- suppcrts 28 and 30, e.g., by 23 inserting the elements 16~ 18, 20, 22, 24, and 26 into 24 mating holes in the Plexiglass suport. The supports 28 and 30 electrically insulate the elements 16, 18, 20, 22, 24 and 26 26 from one anotner, and advantageously are substantially 27 invisible to the resulting electromagnetic wavesf ~ f ~ s /~a~ f~ rk .
-~7~ ~5 S
1 Element 16 is the reflector element, element 18 the 2 driven element, and elements 20, 22, 24 and 26 the director 3 elements. A coa~ial cable 32 is electrically coupled to 4 the driven element 18 for providing a signal thereto.
The reflector 16 and directors 20-26 interact in a conventional S manner to provide increased gain and unidirectivity to the 7 radiated signal pattern. The free-space half-~ower beam-8 widths of element 12A is 42 in the E plane and 48 in the 9 H plane.
Referring to Flg. 3, ten endfire elements 12A-J
11 of the type shown in Fig. 2 are arranged in a linear array 12 lOA. The endfire elements 12A-J have a common reflector 13 16A and are closely spaced laterally a distance of between 14 about 0.3 ~ and about 0.9 ~ apart, preferably about 0.55 ~ apart (center-to-center), to increase thè effects 16 of mutual~coupling therebetween~ With such an arrangement, 17 the in-array pattern, i.e., the angle over whlch the antenna 18 mainlobe can be electronically-scanned increases from 42 19 for the single endfire element 12A of Fig. 2, see the dotted lines and arrows of Fig, 2, to greater than 90 in the 21 array lOA. The narrow H plane pattern of 48 for the 22 single endfire element 12A is maintained in the array lOA~
23 Thus, the effect of closely spacing the endfire elements 12A
24 in the linear array 10 is to broaden the element pattern in the plane of the array lOA (E plane) while preserving the narrow 26 H plane pattern.
~- ~
~ .7~3()SS
., 1 The broadened E-plane pattern o the in-array 2 endfire element may be demonstrated as follows: The elements 3 12A-D and 12F-J have individual terminating impedances 34A-D
4 and 34F-J coupled to ground 36 in the array lOA. The terminating impedances 34A-D and 34F-J are chosen to match S the antenna driving point impedance to an antenna scan angle 7 o~ 0 in the E-plane. In ~he embodiment illustrated in Fig. 3, 8 the terminating impedances 34A-D and 34F-J are 50 ohms.
9 Element 12E is monitored by meter 38 which measures the power received by element 12E when ~he array lOA is used as a 11 receiving device to receive signals transmitted by a 12 radiating device (not shown) positioned at sufficient 13 distance fro~ the array lOA so as to be in the far field 14 of the array lOA. As the array lOA is rotated in angle with respect to the radiating device, the power measured 16 in meter ~8 will vary in proportion to the in-array element l? pattern of element 12E. This method of pattern measurement 18 is well known in the art. Moreover, it is also well known 19 in the art that the in-array element pattern measured in this manner is approximately proportional to the gain of 21 the array lOA as a function of angle when the outputs 22 o all of the elements L2A-J are utilized to io m a beam.
_ g _ ~1'7911~55 ., 1 Wlth reference to Fig. 4, the array lOA operates 2 as follows: A feed means (not shown) applies transmission 3 signals to a combining/dividing network 40 which splits 4 the signals for transmission by the individual elements 42 of the array 44 (N elements are shown). N phase shifters 46 shift the phase of the signals in accordance with the 7 direction in which a beam is desired. In applications where une~ual amplitudes are desired for each antenna 9 element to provide lower antenna sidelobes (co~monly known as amplitude taper), the combining/dividing network 48 11 advantageously provides such a distribution.
12 The antenna array lOA with its feed is linear 13 passive and ~ilateral and is subject to the law of 14 reciprocity so that when it is used in the receiving mode its characteristics are unaltered.
16 Referring to Fig, 5, an aircraft 48 is illustrated 17 with antenna arrays 10 B, C and D in accordance with the 18 present invention positioned in the wing leading edges 19 50 and 52 and in the horizontal stabilizer 54. With this arrangement 360 azimuthal coverage ls obtained by 21 electronically scanning the arrays lOB-D and conventional 22 side-looking antennas 56 and 58 mounted on opposite sides 23 of the ~uselage 60. Advantageously, such an arrangement t4 avoids the need for a large dome mounted on the fuselage 60 which must be mechanically rotated to provide the same 26 360 azimuthal coverage.
~l1'7~)055 1 It should be apparent to those skilled in the 2 art that various modifications may be made in the present 3 invention without departing from the spirit and scope 4 thereof, as described in the specification and defined 6 ln t appended claims.
9 .
13 . ~ .
18 .
~0 24 .
__ __ _, _ _ __ __
Claims (23)
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:
1. An antenna having a linear array of endfire elements, comprising:
a plurality of laterally spaced endfire elements, said endfire elements being spaced from about 0.3 ? to 0.9 ? apart to enhance the effects of mutual coupling therebetween to broaden the element pattern in the plane of the array.
a plurality of laterally spaced endfire elements, said endfire elements being spaced from about 0.3 ? to 0.9 ? apart to enhance the effects of mutual coupling therebetween to broaden the element pattern in the plane of the array.
2. The antenna claimed in Claim 1, wherein:
the spacing between said endfire elements is about 0.55 ? .
the spacing between said endfire elements is about 0.55 ? .
3. The antenna claimed in Claim 1, wherein:
said endfire elements are Yagi endfire elements,
said endfire elements are Yagi endfire elements,
4. The antenna claimed in Claim 1, wherein:
each of said endfire elements includes a driver, a plurality of directors, and a common reflector all fixedly positioned relative to one another each of said endfire elements having a length of approximately 1.25 ? .
each of said endfire elements includes a driver, a plurality of directors, and a common reflector all fixedly positioned relative to one another each of said endfire elements having a length of approximately 1.25 ? .
5. The antenna as claimed in Claim 4, wherein:
said endfire elements include non-conductive support means for fixedly positioning said common reflector, driver and plurality of directors of each endfire element relative to one another and maintaining a spacing of about 0.3 ? to about 0.9 ? between each of said endfire elements.
said endfire elements include non-conductive support means for fixedly positioning said common reflector, driver and plurality of directors of each endfire element relative to one another and maintaining a spacing of about 0.3 ? to about 0.9 ? between each of said endfire elements.
6. The antenna claimed in Claim 5, wherein:
each of said endfire elements includes four directors.
each of said endfire elements includes four directors.
7. The antenna claimed in Claim 6, wherein:
the linear array includes ten endfire elements to broaden the angle limits of the antenna mainbeam to greater than 90° in the E plane while maintaining a narrow H plane pattern.
the linear array includes ten endfire elements to broaden the angle limits of the antenna mainbeam to greater than 90° in the E plane while maintaining a narrow H plane pattern.
8. The antenna claimed in Claim 1, wherein:
said antenna is used with acoustic waves.
said antenna is used with acoustic waves.
9 . An antenna system for conformal mounting on an aircraft for generating an electronically scanned main radiation lobe comprising:
(a) a linear array of Yagi antennas which are laterally spaced from one another a distance of about 0.3 ? to 0.9 ? center to center, each of said Yagi antennas including a driven element, a reflector member and a director member, each of which having a length less than the spacing between each adjacent Yagi antenna, each of said Yagi antennas being operative to radiate:
i. free space beam widths Bx and By in the coordinate X and Y planes, respectively, the values of Bx and.
By being substantially less than 90°; and ii. free space maximum gain in the direction of the lengths of said Yagi antennas; and (b) means for scanning the antenna system main lobe in the X plane over an angle A substantially greater than Bx, while at the same time maintaining a system main lobe beam width in the Y plane which approximates By, said scan angle A being able to be broadened to greater than 90° as a result of enhanced mutual coupling between said Yagi antennas.
(a) a linear array of Yagi antennas which are laterally spaced from one another a distance of about 0.3 ? to 0.9 ? center to center, each of said Yagi antennas including a driven element, a reflector member and a director member, each of which having a length less than the spacing between each adjacent Yagi antenna, each of said Yagi antennas being operative to radiate:
i. free space beam widths Bx and By in the coordinate X and Y planes, respectively, the values of Bx and.
By being substantially less than 90°; and ii. free space maximum gain in the direction of the lengths of said Yagi antennas; and (b) means for scanning the antenna system main lobe in the X plane over an angle A substantially greater than Bx, while at the same time maintaining a system main lobe beam width in the Y plane which approximates By, said scan angle A being able to be broadened to greater than 90° as a result of enhanced mutual coupling between said Yagi antennas.
10. The antenna system of Claim 9 wherein:
The spacing between said Yagi antennas is about 0.55 ?.
The spacing between said Yagi antennas is about 0.55 ?.
11. The antenna system as claimed in Claim 9, wherein:
Bx is approximately 42°.
Bx is approximately 42°.
12. The antenna system of Claim 9 , wherein:
The system main lobe beam width in the Y plane is about 43°.
The system main lobe beam width in the Y plane is about 43°.
13. The antenna system claimed in Claim 9, wherein:
said linear array includes ten Yagi antennas which are arrayed in the E-plane, each Yagi antenna further including three additional director members.
said linear array includes ten Yagi antennas which are arrayed in the E-plane, each Yagi antenna further including three additional director members.
14 The system as defined in Claim 9 , further including means for conformally mounting said Yagi antennas in an aircraft wing.
15. The system as defined in Claim 9, further including (1) a pair of side-looking antennae;
(2) means for conformally mounting said side-looking antennae and said electronically scanned antenna system in an aircraft whereby wide azimuthal coverage is obtained.
(2) means for conformally mounting said side-looking antennae and said electronically scanned antenna system in an aircraft whereby wide azimuthal coverage is obtained.
1 6. The system as defined in Claim 15 wherein there are two of said electronically scanned antenna systems and wherein said mounting means include further means for mounting said two systems in a back-to-back relationship.
1 7. The system as defined in Claim 15 in which said mounting means are adapted to conformally mount said electroni-cally scanned antenna systems within the wing of said aircraft.
18. The system as defined in Claim 16 in which said further means are adapted to conformally mount said two systems in the wing and horizontal stabilizer of said aircraft, respec-tively.
19. The system as defined in Claim 18, wherein said side-looking antenna are conformally mounted on an aircraft fuselage.
20. The antenna system of Claim 9 wherein the reflector member of each of said Yagi antennas is a common reflector member.
21. The antenna system of Claim 9 wherein each Yagi antenna has a length of approximately 1.25 ?.
22. The antenna system of Claim 9 wherein said Yagi antennas include non-conductive support means for fixedly positioning the driven element, reflector member, and driven member of each Yagi antenna relative to one another.
23. The antenna system of Claim 9 in which said driven element, reflector member and director member of each Yagi antenna are spaced from one another a distance of about 0.25?.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA000399442A CA1179055A (en) | 1982-03-25 | 1982-03-25 | Electronically scanned antenna system having a linear array of endfire elements |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA000399442A CA1179055A (en) | 1982-03-25 | 1982-03-25 | Electronically scanned antenna system having a linear array of endfire elements |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1179055A true CA1179055A (en) | 1984-12-04 |
Family
ID=4122420
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000399442A Expired CA1179055A (en) | 1982-03-25 | 1982-03-25 | Electronically scanned antenna system having a linear array of endfire elements |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA1179055A (en) |
-
1982
- 1982-03-25 CA CA000399442A patent/CA1179055A/en not_active Expired
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| US4336543A (en) | Electronically scanned aircraft antenna system having a linear array of yagi elements | |
| JP2851338B2 (en) | Angle Positioning Radar System for Linear Phased Array Antenna | |
| US4594595A (en) | Circular log-periodic direction-finder array | |
| US5926137A (en) | Foursquare antenna radiating element | |
| US5038149A (en) | Antenna with three-dimensional coverage and electronic scanning, of the random spare volume array type | |
| US8854257B2 (en) | Conformal array, luneburg lens antenna system | |
| US5359338A (en) | Linear conformal antenna array for scanning near end-fire in one direction | |
| US20160013564A1 (en) | Antenna system | |
| JPS6137807B2 (en) | ||
| US4186400A (en) | Aircraft scanning antenna system with inter-element isolators | |
| IL221050A (en) | Variable height radiating aperture | |
| JP2004507906A (en) | Dielectric resonator antenna array with steerable elements | |
| US5274390A (en) | Frequency-Independent phased-array antenna | |
| CN108011190B (en) | Multi-frequency-band integrated wide-area detection receiving antenna | |
| US5017931A (en) | Interleaved center and edge-fed comb arrays | |
| EP0807992A1 (en) | Logarithmic spiral array | |
| US4284991A (en) | Common antenna for primary and secondary radar system | |
| US4872016A (en) | Data processing system for a phased array antenna | |
| KR101874103B1 (en) | IFF antenna and Radiating element for implementation of symmetric elevation radiation pattern of IFF antenna | |
| US5923302A (en) | Full coverage antenna array including side looking and end-free antenna arrays having comparable gain | |
| US5986611A (en) | Steerable disk antenna | |
| US4675681A (en) | Rotating planar array antenna | |
| US4021815A (en) | Circularly polarized transmitting antenna employing end-fire elements | |
| CA1179055A (en) | Electronically scanned antenna system having a linear array of endfire elements | |
| EP0104173B1 (en) | An electronically scanned antenna system having a linear array of yagi antennas |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| MKEC | Expiry (correction) | ||
| MKEX | Expiry |