WO2014080298A1 - Circularly polarized slotted waveguide antenna - Google Patents
Circularly polarized slotted waveguide antenna Download PDFInfo
- Publication number
- WO2014080298A1 WO2014080298A1 PCT/IB2013/050567 IB2013050567W WO2014080298A1 WO 2014080298 A1 WO2014080298 A1 WO 2014080298A1 IB 2013050567 W IB2013050567 W IB 2013050567W WO 2014080298 A1 WO2014080298 A1 WO 2014080298A1
- Authority
- WO
- WIPO (PCT)
- Prior art keywords
- waveguide
- circularly polarized
- antenna
- polarized slotted
- section
- 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.)
- Ceased
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Classifications
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01Q—ANTENNAS, i.e. RADIO AERIALS
- H01Q13/00—Waveguide horns or mouths; Slot antennas; Leaky-waveguide antennas; Equivalent structures causing radiation along the transmission path of a guided wave
- H01Q13/02—Waveguide horns
- H01Q13/0233—Horns fed by a slotted waveguide array
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01Q—ANTENNAS, i.e. RADIO AERIALS
- H01Q13/00—Waveguide horns or mouths; Slot antennas; Leaky-waveguide antennas; Equivalent structures causing radiation along the transmission path of a guided wave
- H01Q13/20—Non-resonant leaky-waveguide or transmission-line antennas; Equivalent structures causing radiation along the transmission path of a guided wave
- H01Q13/22—Longitudinal slot in boundary wall of waveguide or transmission line
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01Q—ANTENNAS, i.e. RADIO AERIALS
- H01Q19/00—Combinations of primary active antenna elements and units with secondary devices, e.g. with quasi-optical devices, for giving the antenna a desired directional characteristic
- H01Q19/06—Combinations of primary active antenna elements and units with secondary devices, e.g. with quasi-optical devices, for giving the antenna a desired directional characteristic using refracting or diffracting devices, e.g. lens
- H01Q19/08—Combinations of primary active antenna elements and units with secondary devices, e.g. with quasi-optical devices, for giving the antenna a desired directional characteristic using refracting or diffracting devices, e.g. lens for modifying the radiation pattern of a radiating horn in which it is located
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01Q—ANTENNAS, i.e. RADIO AERIALS
- H01Q21/00—Antenna arrays or systems
- H01Q21/0006—Particular feeding systems
- H01Q21/0037—Particular feeding systems linear waveguide fed arrays
- H01Q21/0043—Slotted waveguides
- H01Q21/005—Slotted waveguides arrays
-
- 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
-
- 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
- H01Q21/064—Two dimensional planar arrays using horn or slot aerials
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01Q—ANTENNAS, i.e. RADIO AERIALS
- H01Q21/00—Antenna arrays or systems
- H01Q21/28—Combinations of substantially independent non-interacting antenna units or systems
Definitions
- This invention is related to slotted waveguide antennas that can receive and transmit electromagnetic waves with circular polarization.
- Circularly polarized slotted waveguide antenna arrays which transmit receive in a directional manner, are realized using slots which are not enabling the control of the aperture amplitude distribution or other slot types which are very hard to manufacture especially at high frequencies.
- all the elements are excited with equal amplitudes and this causes the side lobe level at the far zone of the antenna to be high.
- patent document KRl 00686606 slots are used which are opened on the corners of waveguides exciting the cavity at the upper side. On the top side of the cavities, a PCB (printed circuit board) based polarizer is placed. Since the slot parameters are fixed, the excitation of the slots is not possible. Therefore, the invention in patent document KRl 00686606 does not enable the control of the amplitude distribution of the array.
- patent document US2007273599 open ended waveguide which are fed by waveguides are used and this invention does not enable the control of aperture amplitude distribution.
- the antenna slots are carved on waveguide broad wall with 45° angle and with a fixed offset from waveguide centerline.
- the elliptical structures in which the slots are radiating are used to suppress grating lobes.
- Grating lobes are different than side lobes and they appear due to large inter element spacing in antenna arrays. Suppressing grating lobes does not affect the side lobe level of the antenna and there is no mention of side lobe level reduction in the document.
- the aim of this invention is enabling the reduction of far zone side lobe level of a circularly polarized slotted waveguide antenna array without sacrificing radiation efficiency.
- Figure 1 Perspective view of the antena.
- Sekil Cut view of the antenna.
- Sekil 3 The perspective view of the antenna structure having the polarizing waveguide and a single slot.
- the circularly polarized slotted waveguide antenna which is the subject of this invention (1) basically comprises of:
- At least one secondary waveguide (4) which is placed on top of the surface of the rectangular cross section waveguide (2) on which the slots (3) are carved,
- the circularly polarized slotted waveguide antenna which is the subject of this invention comprises of a rectangular cross section waveguide (2) on which slots (3) are carved and which is exciting the slots (3), slots (3) which are carved on the rectangular waveguide (2), secondary waveguide (4) which is placed on top of the rectangular waveguide (2) positioned with a definite angle ( ⁇ ) with respect to the slots (3).
- TE10 mode excites the slots (3).
- the field distribution created on the slots (3) excites the secondary waveguide (4).
- the fact that secondary waveguide (4) is placed with and angle ( ⁇ ) causes both TE10 and TE01 modes to be excited. To obtain circular polarization, these two modes should be excited with equal amplitudes and they should have a phase difference of 90° between them.
- the parameter controlling the excitation amplitude ratio of the two modes is the placement angle ( ⁇ ) of the secondary waveguide (4). Since there is not an analytical expression relating the excitation amplitude ratio to the secondary waveguide (4) placement angle ( ⁇ ), the angle ( ⁇ ) causing the excitation of the modes TE10 and TE01 with equal amplitudes is determined using numerical electromagnetic simulations. The determined value is generally between 40° and 50°.
- phase difference between TE10 and TE01 modes should be 90° ( ⁇ /2 radian). If it is assumed that the phase difference of the modes on the slot (3) surface ⁇ 0 , the modal electric field expressions at a distance "d" away from the slot (3) surface by neglecting the reflections from the aperture at the upper section of the secondary waveguide (4) are given by:
- ⁇ ⁇ Phase of TE10 mode
- Phase of TE01 mode.
- a and b are the edge lengths of the secondary waveguide (4) cross section (shown in figures), c: speed of the light in vacuum,/- frequency. This expression neglects the reflections at the waveguide (4) aperture and therefore, it is approximate. A more accurate value can be obtained via electromagnetic simulations.
- the cross section of the secondary waveguide (4) should be narrow enough to prevent modes other than TEIO and TEOl from propagating.
- the mode with the lowest cut-off frequency after TEIO and TEOl is the TE/TMl 1 mode.
- the cut-off frequency of the TE/TMl 1 mode,f c u is:
- f max the highest usable frequency of the antenna
- TE10 and TE01 modes are made 90° out of phase at the aperture of the secondary waveguide (4).
- Circularly polarized electric field distribution at the aperture of the secondary waveguide (4) radiates circularly polarized waves into free space. If it is desired to have elliptical polarizations of arbitrary axial ratios instead of circular polarization, the phase difference between modes should be made different than 90°. In this case, the dimensions of the secondary waveguide (4) should be chosen differently from the values given 90° phase difference.
- Excitation amplitude and phase of the slot (3) is controlled by changing the length of the slot (3) and by changing the distance between the slot (3) and the centerline of the waveguide (2) as it is known from the literature. Additionally, depending on the excitation amplitude and phase, the slots (3) can be modeled as shunt admittances for rectangular cross section waveguide (2). By taking advantage of this fact, the amplitude distribution at the apertures of the designed arrays can be easily controlled. This leads to low side lobe level and low cross polarization level slotted waveguide antenna arrays.
- the cross section of the secondary waveguide is elliptical.
- the circularly polarized slotted waveguide antenna (1) which is the subject of this invention is radiating circularly polarized waves without requiring an additional polarizer layer. This enables a fully metal construction which minimizes ohmic losses and increasing antenna efficiency.
Landscapes
- Waveguide Aerials (AREA)
Abstract
The invention is related to slotted waveguide antennas which are used for receiving and transmitting circularly polarized electromagnetic waves. This invention's purpose is to realize a circularly polarized waveguide slot antenna element which enables the control of the antenna array amplitude distribution across the aperture to lower the far zone side lobe levels without sacrificing the antenna efficiency.
Description
DESCRIPTION
CIRCULARLY POLARIZED SLOTTED WAVEGUIDE ANTENNA Field of the Invention
This invention is related to slotted waveguide antennas that can receive and transmit electromagnetic waves with circular polarization.
State of the Art
Circularly polarized slotted waveguide antenna arrays which transmit receive in a directional manner, are realized using slots which are not enabling the control of the aperture amplitude distribution or other slot types which are very hard to manufacture especially at high frequencies. When there is no control over the aperture amplitude distribution of the array, all the elements are excited with equal amplitudes and this causes the side lobe level at the far zone of the antenna to be high. It is also possible to obtain circular polarization by adding a polarizing structure to a linearly polarized antenna. However, losses due to polarizer decrease the antenna efficiency.
In patent document KRl 00686606, slots are used which are opened on the corners of waveguides exciting the cavity at the upper side. On the top side of the cavities, a PCB (printed circuit board) based polarizer is placed. Since the slot parameters are fixed, the excitation of the slots is not possible. Therefore, the invention in patent document KRl 00686606 does not enable the control of the amplitude distribution of the array.
In patent document US2007273599, open ended waveguide which are fed by waveguides are used and this invention does not enable the control of aperture amplitude distribution.
In patent document US2008266195, the antenna slots are carved on waveguide broad wall with 45° angle and with a fixed offset from waveguide centerline. The elliptical structures in which the slots are radiating are used to suppress grating lobes. Grating lobes are different than side lobes and they appear due to large inter element spacing in antenna arrays. Suppressing grating lobes does not affect the side lobe level of the antenna and there is no mention of side lobe level reduction in the document.
Aims For The Development Of The Invention
The aim of this invention is enabling the reduction of far zone side lobe level of a circularly polarized slotted waveguide antenna array without sacrificing radiation efficiency.
Summary of the Invention
The realization of circularly polarized slotted waveguide antenna, to accomplish the aims of the invention is shown in the figures:
Figure 1. Perspective view of the antena.
Sekil 2. Cut view of the antenna.
Sekil 3. The perspective view of the antenna structure having the polarizing waveguide and a single slot.
The parts in the figures are numbered as follows:
1. Antenna
2. Rectangular cross section waveguide
3. Slot
4. Second waveguide
Θ. Second waveguide placement angle
The circularly polarized slotted waveguide antenna which is the subject of this invention (1) basically comprises of:
- At least one rectangular cross section waveguide (2) on which at least one slot (3) is carved,
- At least one secondary waveguide (4) which is placed on top of the surface of the rectangular cross section waveguide (2) on which the slots (3) are carved,
The circularly polarized slotted waveguide antenna which is the subject of this invention comprises of a rectangular cross section waveguide (2) on which slots (3) are carved and which is exciting the slots (3), slots (3) which are carved on the rectangular waveguide (2), secondary waveguide (4) which is placed on top of the rectangular waveguide (2) positioned with a definite angle (θ) with respect to the slots (3).
In the rectangular waveguide (2), TE10 mode excites the slots (3). The field distribution created on the slots (3) excites the secondary waveguide (4). The fact that secondary waveguide (4) is placed with and angle (Θ) causes both TE10 and TE01 modes to be excited. To obtain circular polarization, these two modes should be excited with equal amplitudes and they should have a phase difference of 90° between them.
The parameter controlling the excitation amplitude ratio of the two modes is the placement angle (Θ) of the secondary waveguide (4). Since there is not an analytical expression relating the excitation amplitude ratio to the secondary waveguide (4) placement angle (Θ), the angle (Θ) causing the excitation of the modes TE10 and TE01 with equal amplitudes is determined using numerical
electromagnetic simulations. The determined value is generally between 40° and 50°.
To obtain circular polarization, the phase difference between TE10 and TE01 modes should be 90° (π/2 radian). If it is assumed that the phase difference of the modes on the slot (3) surface φ0, the modal electric field expressions at a distance "d" away from the slot (3) surface by neglecting the reflections from the aperture at the upper section of the secondary waveguide (4) are given by:
TE = Ene
In the above equations,
βιο'. TE10 mode propagation constant, βοι TE01 mode propagation constant, d: Height of the secondary waveguide (4) (shown in figures).
Therefore, the phase difference at a distance "d" from the slot (3) is given by: τΕιο - ΦτΕ0ί = (Λ)1 - βΐθ )ά + Φθ In the above equation,
ΦΤΕιο : Phase of TE10 mode, φΤΕ o| : Phase of TE01 mode.
Propagation constants are expressed as:
To obtain circular polarization, the value of d: height of secondary waveguide (4) is given by:
In the above equation, a and b are the edge lengths of the secondary waveguide (4) cross section (shown in figures), c: speed of the light in vacuum,/- frequency. This expression neglects the reflections at the waveguide (4) aperture and therefore, it is approximate. A more accurate value can be obtained via electromagnetic simulations.
The cross section of the secondary waveguide (4) should be narrow enough to prevent modes other than TEIO and TEOl from propagating. The mode with the lowest cut-off frequency after TEIO and TEOl is the TE/TMl 1 mode. The cut-off frequency of the TE/TMl 1 mode,fcu is:
Therefore, the highest usable frequency of the antenna, fmax should satisfy:
By determining the secondary waveguide (4) cross section edge lengths and the height of the secondary waveguide (4) with the given formulae, TE10 and TE01 modes are made 90° out of phase at the aperture of the secondary waveguide (4). Circularly polarized electric field distribution at the aperture of the secondary waveguide (4) radiates circularly polarized waves into free space. If it is desired to have elliptical polarizations of arbitrary axial ratios instead of circular polarization, the phase difference between modes should be made different than 90°. In this case, the dimensions of the secondary waveguide (4) should be chosen differently from the values given 90° phase difference. Excitation amplitude and phase of the slot (3) is controlled by changing the length of the slot (3) and by changing the distance between the slot (3) and the centerline of the waveguide (2) as it is known from the literature. Additionally, depending on the excitation amplitude and phase, the slots (3) can be modeled as shunt admittances for rectangular cross section waveguide (2). By taking advantage of this fact, the amplitude distribution at the apertures of the designed arrays can be easily controlled. This leads to low side lobe level and low cross polarization level slotted waveguide antenna arrays.
It is possible to create a linear antenna array by placing secondary waveguides (4) on the rectangular waveguide (2) on which a linear array of slots is carved. Parameters of each slot can be tuned to obtain a desired amplitude distribution at the aperture.
It is also possible to use a plurality of linear antenna arrays to create planar, circular cylindrical antenna arrays.
In one embodiment, instead of a rectangular cross section waveguide (2), circular, elliptical or other cross section waveguides with or without ridges can be used.
In one embodiment, the cross section of the secondary waveguide is elliptical.
The circularly polarized slotted waveguide antenna (1) which is the subject of this invention is radiating circularly polarized waves without requiring an additional polarizer layer. This enables a fully metal construction which minimizes ohmic losses and increasing antenna efficiency.
Within the framework of these basic concepts, it is possible to develop a wide variety of embodiments of the inventive circularly polarized slotted waveguide antenna (1). The invention cannot be limited to the examples described herein and it is essentially as defined in the claims.
Claims
1. In most basic form, a circularly polarized slotted waveguide antenna (1) characterized by,
- At least one rectangular cross section waveguide (2) on which at least one slot (3) is carved and,
- At least one secondary waveguide (4) placed on the face of the rectangular waveguide (2) on which slots (3) are carved, which is guiding the radiation emanating from the slots (3).
2. A circularly polarized slotted waveguide antenna (1) as in Claim 1 which is characterized by a secondary waveguide (4) placed on the rectangular cross section waveguide (2) with an angle (Θ) so that both TE10 and TE01 modes are excited inside the secondary waveguide (4).
3. A circularly polarized slotted waveguide antenna (1) as in Claim 1 which is characterized by a secondary waveguide (4) with an angle (Θ) which makes the amplitudes of TE10 and TE01 modes equal or near equal.
4. A circularly polarized slotted waveguide antenna (1) as in Claim 1 which is characterized by a secondary waveguide (4) whose height d satisfies the following equality:
5. A circularly polarized slotted waveguide antenna (1) as in Claim 1 which is characterized by a secondary waveguide (4) whose cross section edge lengths a and b satisfies the following inequality:
6. A circularly polarized slotted waveguide antenna (1) as in Claim 1 which is characterized by a secondary waveguide (4) whose cross section edge lengths are determined in order to create elliptical polarization of a desired axial ratio.
7. A circularly polarized slotted waveguide antenna (1) as in Claim 1 which is characterized by a secondary waveguide (4) with elliptical cross section.
8. A circularly polarized slotted waveguide antenna (1) as in Claim 1 which is characterized by a waveguide of arbitrary cross section like circular, elliptical etc., with or withour ridges inside, instead of a rectangular waveguide (2).
9. A circularly polarized slotted waveguide antenna (1) array which is characterized by a plurality slots (3) carved on rectangular waveguide (2) as in Claim 1 and a plurality of secondary waveguides (4) placed on the rectangular waveguide (2) such that slots (3) will radiate into secondary waveguides (4) as in Claim 1.
10. An antenna array characterized by a plurality of circularly polarized slotted waveguide antenna (1) arrays as in Claim 9 which are arranged to form planar, circular or cylindrical arrays.
Priority Applications (3)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| EP13707719.4A EP2923415B1 (en) | 2012-11-22 | 2013-01-23 | Circularly polarized slotted waveguide antenna |
| ES13707719T ES2773269T3 (en) | 2012-11-22 | 2013-01-23 | Circularly polarized grooved waveguide antenna |
| LU92506A LU92506B1 (en) | 2012-11-22 | 2013-01-23 | Circular polarized slit waveguide antenna |
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| TR2012/13546 | 2012-11-22 | ||
| TR201213546 | 2012-11-22 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| WO2014080298A1 true WO2014080298A1 (en) | 2014-05-30 |
Family
ID=47827398
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| PCT/IB2013/050567 Ceased WO2014080298A1 (en) | 2012-11-22 | 2013-01-23 | Circularly polarized slotted waveguide antenna |
Country Status (4)
| Country | Link |
|---|---|
| EP (1) | EP2923415B1 (en) |
| ES (1) | ES2773269T3 (en) |
| LU (1) | LU92506B1 (en) |
| WO (1) | WO2014080298A1 (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2017175782A1 (en) * | 2016-04-05 | 2017-10-12 | Nidec Elesys Corporation | Waveguide device and antenna array |
| CN113193345A (en) * | 2021-04-30 | 2021-07-30 | 中国电子科技集团公司第三十八研究所 | S-shaped caliber circularly polarized antenna unit and array surface antenna |
Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB507473A (en) * | 1936-09-15 | 1939-06-14 | Otto Bormann | Improvements in or relating to coupling devices for use in the production, amplification or reception of ultra-short waves |
| US20060164315A1 (en) * | 2002-05-21 | 2006-07-27 | Marco Munk | Hollow waveguide sector antenna |
| KR100686606B1 (en) | 2005-11-02 | 2007-02-26 | 위월드 주식회사 | Waveguide Slot Array Antenna for Circularly Polarized Reception |
| US20070273599A1 (en) | 2006-05-24 | 2007-11-29 | Adventenna, Inc. | Integrated waveguide antenna and array |
| US20080117114A1 (en) * | 2006-05-24 | 2008-05-22 | Haziza Dedi David | Apparatus and method for antenna rf feed |
| US20080266195A1 (en) | 2005-03-03 | 2008-10-30 | Satoshi Yamaguchi | Waveguide Slot Array Antenna Assembly |
-
2013
- 2013-01-23 WO PCT/IB2013/050567 patent/WO2014080298A1/en not_active Ceased
- 2013-01-23 ES ES13707719T patent/ES2773269T3/en active Active
- 2013-01-23 EP EP13707719.4A patent/EP2923415B1/en active Active
- 2013-01-23 LU LU92506A patent/LU92506B1/en active
Patent Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB507473A (en) * | 1936-09-15 | 1939-06-14 | Otto Bormann | Improvements in or relating to coupling devices for use in the production, amplification or reception of ultra-short waves |
| US20060164315A1 (en) * | 2002-05-21 | 2006-07-27 | Marco Munk | Hollow waveguide sector antenna |
| US20080266195A1 (en) | 2005-03-03 | 2008-10-30 | Satoshi Yamaguchi | Waveguide Slot Array Antenna Assembly |
| KR100686606B1 (en) | 2005-11-02 | 2007-02-26 | 위월드 주식회사 | Waveguide Slot Array Antenna for Circularly Polarized Reception |
| US20070273599A1 (en) | 2006-05-24 | 2007-11-29 | Adventenna, Inc. | Integrated waveguide antenna and array |
| US20080117114A1 (en) * | 2006-05-24 | 2008-05-22 | Haziza Dedi David | Apparatus and method for antenna rf feed |
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2017175782A1 (en) * | 2016-04-05 | 2017-10-12 | Nidec Elesys Corporation | Waveguide device and antenna array |
| JP2019514281A (en) * | 2016-04-05 | 2019-05-30 | 日本電産株式会社 | Waveguide device and antenna array |
| US10594045B2 (en) | 2016-04-05 | 2020-03-17 | Nidec Corporation | Waveguide device and antenna array |
| CN113193345A (en) * | 2021-04-30 | 2021-07-30 | 中国电子科技集团公司第三十八研究所 | S-shaped caliber circularly polarized antenna unit and array surface antenna |
Also Published As
| Publication number | Publication date |
|---|---|
| ES2773269T3 (en) | 2020-07-10 |
| LU92506B1 (en) | 2014-11-22 |
| EP2923415A1 (en) | 2015-09-30 |
| EP2923415B1 (en) | 2019-12-18 |
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