Claims:WE CLAIM:
1. A KU-band dish antenna (100), comprising:
a feed horn (102); and
a parabolic surface (101), wherein the parabolic surface (101) comprises a plurality of perforations (201), wherein each perforation has a diameter of about 2.5mm and each perforation is separated from adjacent perforations by at least 6mm, wherein the parabolic surface (101) is configured to reflect KU-band signals.

2. The KU-band dish antenna (100) as claimed in claim 1, wherein the diameter of the plurality of perforations (201) is determined using the formula D = ?/10, where ? is a wavelength of the KU band signal.

3. The KU-band dish antenna (100) as claimed in claim 1, wherein the parabolic surface (101) is configured to withstand windspeed up to 40m/s.

4. The KU-band dish antenna (100) as claimed in claim 3, wherein the parabolic surface (101) is configured to withstand wind from angles including 0-360o.

5. The KU-band dish antenna (100) as claimed in claim 1, wherein a diameter of the reflector surface (101) is a factor of the wavelength of the KU band signal.

6. The KU-band dish antenna (100) as claimed in claim 1, wherein a degradation of the KU band signal is less than 0.5dB.

7. The KU-band dish antenna (100) as claimed in claim 1, wherein the feed horn (102) comprises a Low Noise Blockdown (LNB) converter for reducing noise in signals received by the feed horn (102).

8. The KU-band dish antenna (100) as claimed in claim 1, wherein the feed horn (102) is positioned at a predefined distance from the parabolic surface (101).
, Description:TECHNICAL FIELD
The present disclosure relates to a dish antenna. The present invention specifically discloses KU-band dish antenna having a perforations on a reflector.

BACKGROUND
A dish antenna, also commonly known as a dish, is used in a microwave system. The microwave systems are generally used for satellite communication, broadcasting, space communications, and radio astronomy etc. A dish antenna consists of an active or driven element and a passive parabolic or spherical reflector. The driven element can be a dipole antenna or a horn antenna. Generally, the reflector has a diameter of at least several wavelengths and as the wavelength increases (and the frequency decreases), the minimum required dish diameter increases.

When the driven element is properly positioned and aimed towards the reflector, incoming electromagnetic fields bounce off the reflector, and the energy converges on the driven element. For satellite television reception, Low Noise Block down converter (LNB) is used as the driven element which receives the converged satellite signal from the dish reflector, down converts the received energy and sends it via coaxial cable to a receiver for further processing. Likewise, during transmission, the driven element focusses a beam of energy on the reflector, and the reflector broadcasts the energy into space.

The efficiency of transmitting or receiving signals is based on various factors including geometry of the reflector, position of the driven element, material type of the reflector, direction of the reflector, type of connectors used in the antenna, environmental factors such as rain and wind, and the like. To increase the efficiency, the dish antenna is mounted in a specific manner.

In few geographical locations, due to harsh weather the dish antenna is often damaged or displaced. Hence, media is frequently disconnected and incurs huge cost in replacing new dish antenna. Few solutions exists that address the above problem, however such solutions do not account to efficiency. Therefore, there exists a need for an antenna that address the above problem while still reflecting the energy efficiently.

The information disclosed in this background of the disclosure section is only for enhancement of understanding of the general background of the invention and should not be taken as an acknowledgment or any form of suggestion that this information forms the prior art already known to a person skilled in the art.

SUMMARY
Additional features and advantages are realized through the techniques of the present disclosure. Other embodiments and aspects of the disclosure are described in detail herein and are considered a part of the claimed disclosure.

In an embodiment, the present disclosure discloses a KU-band dish antenna. The dish antenna comprises a feed horn, and a parabolic surface. The parabolic surface comprises a plurality of perforations, each perforation having a diameter of about 2.5mm and each perforation is separated from adjacent perforation by at least 6mm. The reflector surface having the plurality of perforations provides stability against strong winds while capturing most of incoming signals.

In an embodiment, the diameter of the plurality of perforations is determined using the formula D = ?/10, where ? is a wavelength of the KU band signal.

In an embodiment, the parabolic surface is configured to withstand windspeed up to 40m/s.

In an embodiment, the parabolic surface is configured to withstand wind from angles including 0-360o.

In an embodiment, a diameter of the reflector surface is a factor of the wavelength of the KU band signal.

In an embodiment, a degradation of the KU band signal is less than 0.5dB.

In an embodiment, the feed horn comprises a Low Noise Blockdown (LNB) converter for reducing noise in signals received by the feed horn.

In an embodiment, the feed horn is positioned at a predefined distance from the parabolic surface.

The foregoing summary is illustrative only and is not intended to be in any way limiting. In addition to the illustrative aspects, embodiments, and features described above, further aspects, embodiments, and features may become apparent by reference to the drawings and the following detailed description.

BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS
The novel features and characteristic of the disclosure are set forth in the appended claims. The disclosure itself, however, as well as a preferred mode of use, further objectives, and advantages thereof, may best be understood by reference to the following detailed description of an illustrative embodiment when read in conjunction with the accompanying drawings. The accompanying drawings, which are incorporated in and constitute a part of this disclosure, illustrate exemplary embodiments and, together with the description, serve to explain the disclosed principles. In the figures, the left-most digit(s) of a reference number identifies the figure in which the reference number first appears. One or more embodiments are now described, by way of example only, with reference to the accompanying figures wherein like reference numerals represent like elements and in which:

Fig. 1 shows structure of a KU-band dish antenna, in accordance with some embodiments of the present disclosure;

Fig. 2 shows an exemplary structure of a reflector surface of a KU-band dish antenna, in accordance with some embodiments of the present disclosure;

Fig. 3 illustrates measuring strain on a reflector surface of a KU-band dish antenna, in accordance with some embodiments of the present disclosure;

Fig. 4 shows an exemplary layout of wind tunnel test set up, in accordance with some embodiments of the present disclosure;

Fig. 5 illustrates direction of wind in a wind tunnel test set up of Fig. 4, in accordance with some embodiments of the present disclosure; and

Fig. 6, Fig. 7 and Fig. 8 show graphs illustrating strain measured on the reflector surface of a KU-band dish antenna, in accordance with some embodiments of the present disclosure;

It should be appreciated by those skilled in the art that any block diagrams herein represent conceptual views of illustrative systems embodying the principles of the present subject matter. Similarly, it may be appreciated that any flow charts, flow diagrams, state transition diagrams, pseudo code, and the like represent various processes which may be substantially represented in computer readable medium and executed by a computer or processor, whether or not such computer or processor is explicitly shown.

DETAILED DESCRIPTION
In the present document, the word "exemplary" is used herein to mean "serving as an example, instance, or illustration." Any embodiment or implementation of the present subject matter described herein as "exemplary" is not necessarily to be construed as preferred or advantageous over other embodiments.

While the disclosure is susceptible to various modifications and alternative forms, specific embodiment thereof has been shown by way of example in the drawings and may be described in detail below. It should be understood, however that it is not intended to limit the disclosure to the particular forms disclosed, but on the contrary, the disclosure is to cover all modifications, equivalents, and alternative falling within the scope of the disclosure.

The terms “comprises”, “includes” “comprising”, “including” or any other variations thereof, are intended to cover a non-exclusive inclusion, such that a setup, device or method that comprises a list of components or steps does not include only those components or steps but may include other components or steps not expressly listed or inherent to such setup or device or method. In other words, one or more elements in a system or apparatus proceeded by “comprises… a” or “includes…a” does not, without more constraints, preclude the existence of other elements or additional elements in the system or apparatus.

In the following detailed description of the embodiments of the disclosure, reference is made to the accompanying drawings that form a part hereof, and in which are shown by way of illustration specific embodiments in which the disclosure may be practiced. These embodiments are described in sufficient detail to enable those skilled in the art to practice the disclosure, and it is to be understood that other embodiments may be utilized and that changes may be made without departing from the scope of the present disclosure. The following description is, therefore, not to be taken in a limiting sense.

Fig. 1 shows a KU-band dish antenna (100). The KU-band dish antenna (100) comprises a reflector surface (101), a feed horn (102) and a base (103). In an embodiment, the KU-band dish antenna (100) operates at KU band (frequency range of 10.7GHz – 12.75GHz or wavelength range of 2.8cm – 2.4cm). The reflector surface (101) also commonly known as parabolic reflector is configured to reflect KU-band signals. The feed horn (102) is configured to receive the reflected KU-band signals from the reflector surface (101) and transmit the KU-band signals to the reflector surface (101). In an embodiment, the KU-band antenna (100) can be configured as a transmitting antenna or a receiving antenna or both. In a full duplex communication system, the KU-band antenna (100) may be configured as for transmitting the KU-band signals and receiving the KU-band signals simultaneously. Generally, the KU-band antenna (100) is used for media streaming applications, and the KU-band antenna (100) is configured as a receiving antenna. The KU-band antenna (100) is configured to receive the KU-band signals comprising media data, from one or more communication satellites.

In an embodiment, the feed horn (102) is configured to receive and provide the KU-band signals from and to the reflector surface (101). During reception, the reflector surface (101) receives incoming KU-band signals and reflects the KU-band signals towards the feed horn (102). In one instance, the feed horn (102) converts the radio frequency signals into electrical signals. The feed horn (102) comprises a Low Noise Block-down (LNB) converter (not shown in Fig. 1) configured to amplify the KU-band signals and filter noise. The LNB converts the high KU-band frequencies into lower frequencies for communicating via the co-axial cables to a processing unit (not shown in Fig. 1). The processing unit processes the Radio Frequency (RF) signals and streams media on a media device such as a television or phone. In an embodiment, the media may be a Moving Picture Experts Group (MPEG)-2 or MPEG-4 signal format. The processing units converts the MPEG-2 or MPEG-4 signal into appropriate electrical signal for displaying on the media device.

In an embodiment, the base (103) is configured to support the of the KU-band antenna (100). In an embodiment, the base (103) may be shaped in a form of legs. Ideally, three legs are used for support. In some embodiments, the base (103) is secured to ground using fasteners.

Fig. 2 shows an exemplary structure of the reflector surface (101) of the KU-band dish antenna (100). In an embodiment, the reflector surface (101) is shaped as a parabola as the parabolic shape helps in directing the incoming KU-band signals to the feed horn (102). As shown in the Fig. 2, the reflector surface (101) comprises a plurality of perforations (201). In an embodiment, the plurality of perforations (201) are made for wind to pass through the KU-band dish antenna (100) for increasing sturdiness of the KU-band dish antenna (100). In one embodiment, the plurality of perforations (201) may be in a pattern or may be randomly distributed over the reflector surface (101). The plurality of perforations (201) may be in different shapes. For example, the each perforations (201) may be in circular share, a rectangular shape, or any other shape. Shape and number of perforations shown in the Fig. 2 is only an exemplary representation and should not be considered as a limitation.

Fig. 2 further shows a zoomed view (202) of a section of the reflector surface (101). In the zoomed view (202) the distance (d1) between adjacent perforations, and diameter (d2) of a perforation are represented. In an embodiment the diameter (d2) of each perforation is about 2.5mm and the distance (d2) is at least 6mm. In an embodiment, to maximize Signal to Noise Ratio (SNR), the diameter (d2) of the perforation is determined to be about one tenth of the wavelength of the KU-band signal. Therefore, the diameter (d2) is determined using the following equations:

? = c / f (1)
where,
c - speed of light (3*10^8 m/s)
f - frequency of KU-band signal (e.g., 11.7GHz)

Using the equation (1), the wavelength is determined to be 25.64mm. Hence, the diameter (d2) is determined to be about 25.64 / 10 = 2.564mm. Further, it is determined that the distance (d1) of at least 6mm maximizes the SNR. In an embodiment, the above dimensions of the plurality of perforations (201) provides higher stability to the KU-band dish antenna (100) and can withstand windspeed up to 40m/s. Further, the above dimensions of the plurality of perforations (201) enables the KU-band dish antenna (100) to withstand wind blowing from angles including 0-360o.

Signal to Noise Ratio (SNR) or Carrier over Noise (C/N) for a satellite dish will degrade due to perforations or holes in the dish reflector. The degradation or signal loss will increase as the hole diameter and the number of holes increases. The degradation depends on the Shielding Effectiveness (SE) of the reflector. Signal loss is given by:

Loss=-10Log(1-10^(-SE/10)) (2)
Where, SE=40Log(?/2d)-20Log(n) (3)
? : Wavelength of signal received,
d : diameter of holes
n : number of holes within ?/2

For d = 2.5mm and n = 3, the loss is 0.0569db from equations 2 and 3. Further, SE = 18.86 dB. When a solid dish antenna has an SNR (C/N) = 16, then the perforated antenna has an SNR of 16 – 0.0569 = 15.94 dB.

In an embodiment, the reflector surface (101) is made of fiberglass or metal, usually aluminum. The plurality of perforations (201) are formed by punching holes in the reflector surface (101). In an embodiment, known techniques of punching holes may be employed. For example, a twist drill, a hand punch, a knockout punch may be used. In some embodiments, laser drilling may also be employed.

Generally, after the KU-band antenna (100) is manufactured, it has to be tested for stability against high speed winds blowing from different angles. Fig. 3 illustrates measuring strain on the reflector surface (101) of the KU-band dish antenna (100). In an embodiment, one or more strain gauges are mounted on the reflector surface (101) to measure a strain on the reflector surface (101) due to the wind. In an exemplary embodiment, the one or more strain gauges are mounted on a rear side of the reflector surface (101). As shown in Fig. 3, a plurality of strain gauges are mounted on the reflector surface (101) along a horizontal axis and a vertical axis. The plurality of strain gauges mounted on the horizontal axis are represented as H0, H1, H2, H3 and H4. The plurality of strain gauges mounted on the vertical axis are represented as V0, V1, V2, V3, V4 and V5. In an embodiment, the plurality of strain gauges may be analog gauges or digital gauges. The strain is measured to determine a displacement or deformation of the reflector surface (101) caused due to the wind.

Fig. 4 show an exemplary layout of wind tunnel test set up, in accordance with some embodiments of the present disclosure. The effect of wind load on the reflector surface (101) is determined accurately using wind tunnel analysis. In an embodiment, the wind load on the KU-band dish antenna (100) is calculated using below equation:

Fw = Cd * qv * A (4)

Where
Fw : wind load
Cd : drag coefficient
qv : wind pressure
A : windward projection area

In an embodiment, the wind tunnel testing stimulates the natural environment accurately. The wind tunnel test is performed in a wind tunnel lab. Fig. 4, shows an exemplary wind tunnel test set up in a laboratory. The wind tunnel set up comprises a fan (301), a diffuser (302), a test section (303), a contraction cone (304), a settling chamber (305) and honeycomb and screens (306).

The features of the test set up comprises a return circuit and a continuous closed jet. The features of the test set up further comprises interchangeable test sections, a cross-section of 3 m × 2.25 m, a length of 5.75 m (upstream part) + 3 m (downstream part), a contraction ratio of 9:1, maximum wind speed of 80 m/s, wind incident angles ranging from 0 to 360 degrees, Reynolds number of 5 x 106 /m, a fan comprising 4.64 m diameter and 12 blades, and a variable speed DC motor having rated power of 1000KW.

The fan (301) is used to move the air inside a tunnel and is located on a far side of the tunnel. In Fig. 4, the air moves counter-clockwise around the circuit. The fan (301) is powered by the 1000KW, variable speed DC motor.

The diffuser (302) is located at an end of the test section (303), and is configured to maintain a smooth movement of the air toward a back of the tunnel. The diffuser (302) also increases in volume so as to slow the air down as the air exits the tunnel.

The test section (303) includes test sensors.

The contraction cone (304) forces a large volume of air through a small opening so as to increase the wind velocity in the tunnel.

The settling chamber (305) is at a front side of the wind tunnel. It is made up of screens and the honeycomb-shaped mesh, which straighten out the air and reduce turbulence.

In an embodiment, the KU-band dish antenna (100) is mounted on a turning table (not shown in Fig. 4) in the laboratory. In an exemplary embodiment, a diameter of the turning table may be 2.4m. The turning table enables wind angles ranging from 0-360o. In an embodiment, the turning table may be remotely controlled using a controller. Fig. 5 illustrates direction of wind in the wind tunnel test set up, in accordance with some embodiments of the present disclosure. As described above, the different wind angles are provided using the turning table. Further, the test is conducted at different wind speeds. In an exemplary embodiment, the KU-band dish antenna (100) may be tested to withstand uniform windspeed of 20m/s. In an exemplary embodiment, the KU-band dish antenna (100) may be tested to withstand uniform windspeed of 30m/s. In an exemplary embodiment, the KU-band dish antenna (100) may be tested to withstand uniform windspeed of 40m/s. In an exemplary embodiment, the KU-band dish antenna (100) may be tested to withstand uniform windspeed of 50m/s. In one embodiment, for each of the above windspeeds, the wind may be provided from the different angles. Fig. 6 shows a graph illustrating strain measurement on the reflector surface (101) at windspeed of 20m/s for different wind angles. The KU-band dish antenna (100) is stable at windspeed of 20m/s for the different wind angles. Fig. 7 shows a graph illustrating strain measurement on the reflector surface (101) at windspeed of 30m/s for different wind angles. The KU-band dish antenna (100) is stable at windspeed of 30m/s for the different wind angles. Fig. 8 shows a graph illustrating strain measurement on the reflector surface (101) at windspeed of 40m/s for different wind angles. The KU-band dish antenna (100) is stable at windspeed of 40m/s for the different wind angles, excluding windspeed of 220o and 240o. At windspeed of 220o and 240o, although abnormal vibrations are seen, the KU-band dish antenna (100) is stable and may not collapse. Hence the Ku-Band dish antenna (100) is stable even at high wind speed and at different wind angles.

The proposed KU-band dish antenna (100) is stable even under high wind loads and may withstand wind blowing at different speeds and from different angles. Hence, the proposed KU-band dish antenna (100) may be installed in high terrain sites and high wind load regions. Further, the KU-band dish antenna (100) has a signal loss less than 0.5dB even at high wind load conditions. Therefore, the media is undisturbed even during windy conditions.

The terms "an embodiment", "embodiment", "embodiments", "the embodiment", "the embodiments", "one or more embodiments", "some embodiments", and "one embodiment" mean "one or more (but not all) embodiments of the invention(s)" unless expressly specified otherwise.
The terms "including", "comprising", “having” and variations thereof mean "including but not limited to", unless expressly specified otherwise.

The enumerated listing of items does not imply that any or all of the items are mutually exclusive, unless expressly specified otherwise. The terms "a", "an" and "the" mean "one or more", unless expressly specified otherwise.

A description of an embodiment with several components in communication with each other does not imply that all such components are required. On the contrary, a variety of optional components are described to illustrate the wide variety of possible embodiments of the invention.

When a single device or article is described herein, it may be readily apparent that more than one device/article (whether or not they cooperate) may be used in place of a single device/article. Similarly, where more than one device or article is described herein (whether or not they cooperate), it may be readily apparent that a single device/article may be used in place of the more than one device or article or a different number of devices/articles may be used instead of the shown number of devices or programs. The functionality and/or the features of a device may be alternatively embodied by one or more other devices which are not explicitly described as having such functionality/features. Thus, other embodiments of the invention need not include the device itself.

Finally, the language used in the specification has been principally selected for readability and instructional purposes, and it may not have been selected to delineate or circumscribe the inventive subject matter. It is therefore intended that the scope of the invention be limited not by this detailed description, but rather by any claims that issue on an application based here on. Accordingly, the disclosure of the embodiments of the invention is intended to be illustrative, but not limiting, of the scope of the invention, which is set forth in the following claims.

While various aspects and embodiments have been disclosed herein, other aspects and embodiments may be apparent to those skilled in the art. The various aspects and embodiments disclosed herein are for purposes of illustration and are not intended to be limiting, with the true scope and spirit being indicated by the following claims.

REFERRAL NUMERALS:

Reference number Description
100 KU-band dish antenna
101 Reflector surface
102 Feed horn
103 Base
201 Perforations
202 Zoomed view
301 Fan
302 Diffuser
303 Test section
304 Contraction cone
305 Settling chamber
306 Honeycomb and screens