Antenna arrays principles and properties are discussed using an interactive applet. Antenna arrays are formed by assembling identical in most cases radiating elements such as dipoles for example.
In the diagram below is shown an antenna array with its elements along the z axis such that the distance between each two successive elements is equal to d. Antenna arrays are characterized by their array factor which is given by the formula.
The main objective of the tutorial below is to explore how each of the parameters N, d and affect the radiating pattern of the array. On the left panel, you may use any of the sliders to change N the number of elements making the arrayd the distance between the elements and the phase. Note that the array is more directional. If you change to For these values of we have end-fire radiation. For this value of we have broadside radiation. Note that the direction of maximum radiation changes.
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Answer : Antenna is a transition device or a transducer between a guided wave and a free space wave or vice-versa. Antenna is also said to be an impedance transforming device.
Question 2. Answer : Radiation pattern is the relative distribution of radiated power as a function of distance in space. It is a graph which shows the variation in actual field strength of the EM wave at all points which are at equal distance from the antenna. Question 3. Define Radiation Intensity? Answer : The power radiated from an antenna per unit solid angle is called the radiation intensity U watts per steradian or per square degree. The radiation intensity is independent of distance.
Question 4. Define Beam Efficiency? Question 5. Define Directivity? Answer : The directivity of an antenna is equal to the ratio of the maximum power density P q,f max to its average value over a sphere as observed in the far field of an antenna. Question 6. Answer : Effective aperture. Scattering aperture. Loss aperture. Collecting aperture. Physical aperture. Question 7. Define Different Types Of Aperture?
Answer : Effective aperture Ae : It is the area over which the power is extracted from the incident wave and delivered to the load is called effective aperture. Scattering aperture As : It is the ratio of the reradiated power to the power density of the incident wave.
Multiple Choice Questions and Answers on Antenna & Wave Propagation
Loss aperture Ae : It is the area of the antenna which dissipates power as heat. Question 8. Define Aperture Efficiency? Answer : The ratio of the effective aperture to the physical aperture is the aperture efficiency. Question 9. Answer : The effective height h of an antenna is the parameter related to the aperture. It may be defined as the ratio of the induced voltage to the incident field.
Question What Are The Field Zones?SONAR b. Subsurface communication c. Radio navigation d. Phase b. Frequency c. Amplitude d. Wave equation. Sinusoidal b. Rectangular c. Square d. Solid bodies b. Ionized particles c. All of the above. Reflected b. Refracted c. Radiated d. D-region b. Normal E-region c. Sporadic E-region d. Appleton region. Electric field intensity b. Magnetic field intensity c. Current density d.An antenna, when individually can radiate an amount of energy, in a particular direction, resulting in better transmission, how it would be if few more elements are added it, to produce more efficient output.
It is exactly this idea, which led to the invention of Antenna arrays. An antenna array can be better understood by observing the following images. Observe how the antenna arrays are connected. An antenna array is a radiating system, which consists of individual radiators and elements.
Each of this radiator, while functioning has its own induction field. Therefore, the radiation pattern produced by them, would be the vector sum of the individual ones.
The following image shows another example of an antenna array. The spacing between the elements and the length of the elements according to the wavelength are also to be kept in mind while designing these antennas. The antennas radiate individually and while in array, the radiation of all the elements sum up, to form the radiation beam, which has high gain, high directivity and better performance, with minimum losses.
The antenna-array tag has no usage guidance. Home Questions Tags Users Unanswered. Questions tagged [antenna-array]. Ask Question. Learn more… Top users Synonyms. Filter by. Sorted by. Tagged with. Apply filter. Why can the polarization of an antenna array be determined by the polarization of its individual elements? In problems determining the polarization of an antenna array I've looked at, the polarization of the total array is determined by finding the polarization of a single element and then extrapolating Jimmy Vailer 1 1 silver badge 11 11 bronze badges.
The board has 3 TX patch antennas and 4 RX patch antennas. I am trying to simulate the patch antenna in CST. TI has provided their Prudhvi Sagar 1. We need to add RFID tags to feeders on our pick and place machine, to determine that they are loaded into the Kyle Hunter 2 2 silver badges 13 13 bronze badges. Satellite array antenna beamforming - basic intuition help When you see a satellite coverage region on the earth, the array antennas form tens of circles small coverages in a large coverage.
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How to design a 3GHz antenna? S11 has to be below dB and the gain to be above 9dBi - and I want to make it smaller than 8cm. What kind of antenna is better to satisfy thePisces Weekly Horoscope You continue to be lucky Pisces and you have always been a believer.
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The company uses Like2Buy to make it easier for its Instagram followers to shop its feed. Retail-centric apps and services are also common in the fulfillment space. Take Apple, for example.
The company has teamed up with logistics company Postmates to offer same-day delivery to its customers. Instead, they can just wait for an expert from Enjoy to hand-deliver their new phones and get them set up.
Ryan Baker, Co-Founder and CEO, Timely. While this creates opportunities to succeed, it also strains your most valuable resource: time. One of the greatest resources that any business owner and especially those in retail can hope to tame is time. Taking control over your schedule, your admin, and ultimately the successful operation of your business means equipping yourself with the necessary tools to handle the job so you can get back to dealing with what is most important: your customer.
Not all tools are created equal, nor do they all play nicely together. Moving into 2017, it will be more important than ever to have tech solutions that work well together. Ensuring your business is perfectly synced means choosing apps that both make your life easier and integrate seamlessly to maximize their overall benefits.
Your point of difference as a retailer is the experience you offer to your customers, so every tool you implement should be with them in mind. Retail and technology will become even more inseparable.
As part of the effort to provide consumers with better experiences, retailers will incorporate technology even further into their businesses. In 2017, evolving technology in the retail industry will be instrumental in enticing customers into physical stores and in creating seamless omnichannel shopping experiences. Artificial intelligence, augmented and virtual reality, and the Internet of Things will stake firm claims in retail as tools that brick and mortar and online retailers alike can use to further elevate and personalize each step of the process.
Augmented reality that allows consumers to virtually experience products as they might use them in their own lives, smart dressing rooms in fashion stores, and glass touchscreens as interactive components of storefronts. Many small and medium businesses will adopt retail technologies as well. Expect to see SMBs roll out loyalty apps, customer displays, and other solutions that take the shopping experience to a new level. Now an SMB retailer can have its own mobile ordering app and its own internal employee management app, launched within days.
This has also led to the increased integration of direct customer interaction via customer displays, menu boards, loyalty applications, and many other ways that really make the consumer feel much more a part of the process. Seamless omnichannel strategies will once and for all become absolutely essential, and retail will propel itself into the future through implementation of experience-enhancing technology such as artificial intelligence and augmented reality.
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