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Questions tagged [antenna]

Antenna (radio), also known as an aerial, a transducer designed to transmit or receive electromagnetic (e.g. TV or radio) waves. -Wikipedia

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Atenna Gain diagram to power diagram

I have a 3d gain diagram from a antena. How to calculate the power of this antena? Thanks!
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Tuning capacitance-matching circuit

I have designed an antenna for a WPT application. We already have a primary coil with a centered frequency of 13.56 MHz. We want to match the second coil at the same frequency and that's why we need ...
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1answer
274 views

How is the magnetic field radiated in a microstrip patch antenna?

If we talk about dipoles or any other antenna, we discuss the electric field as well as the magnetic field. But while discussing micro-strip antennas, only the electric field is explained. Why? EM ...
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How to choose an antenna for an FM transmitter? [duplicate]

Ok guys I can't understand something. Say that I have this circuit: Assuming that I apply at the antenna 5V, how can I calculate how much power I will trasmit? I found on internet that the current ...
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42 views

Is there any active GSM antenna exist? [closed]

Active antenna amplifies received signals with active components, so it has better parameters. Active antenna for the only receiving systems like GPS and TV signals are exist on the shelves. But the ...
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189 views

Am I exposed to high levels of radiation at my job? [closed]

I made this post because I have a safety concern about my job as medical device tester. I was reading the user manual of the equipment I work with and found the next warning: “Per FCC regulations, ...
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HFSS SAR anlysis Calculation

I am calculating The SAR anlysis on a human head of a wearable antenna that i have made . I have added a waveguide port and after simulation it does not show the radiation pattern using the HFSS ...
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54 views

How to design a 3GHz antenna? [closed]

I would like to design a 3GHz high gain antenna. S11 has to be below -10dB and the gain to be above 9dBi - and I want to make it smaller than 8cm. What kind of antenna is better to satisfy the ...
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1answer
75 views

How does an antenna tune in a particular frequency on the receiver side?

When an electromagnetic wave strike an antenna, a current starts to flow in it. There are many EM waves (at different frequencies) around us. Does this mean that there is always current flowing in ...
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47 views

How does DTH (satellite receiver at home) convert EM waves into an electrical signal?

Any DTH consist of a parabolic reflector, a feedhorn, a waveguide, LNBF etc. The signal passes from the parabolic reflector to LNBF via feedhorn and waveguide. Upto waveguide the signals are in the ...
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1answer
39 views

why we use LNBF instead of simple dipole antenna, at the focal point of reflector of satellite dish antenna?

LNBF is made of horn antenna, waveguide, half/quarter wave dipole and some circuitry on PCB. I know Horn antenna is used to match impedance between waveguide and free space but my doubt is, why we ...
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61 views

Can single conducting straight wire can radiate EM wave or we need two bend conducting wire similar to dipole antenna? [closed]

Actually I have read somewhere that there is no radiation if wire is straight. If it is true then why people are explaining antenna radiation with straight wire diagram?
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Antenna Design in relation to RLC circuit

I am having trouble understanding how antennas can be "represented" as an RLC circuit; how do these two concepts, antenna design and RLC circuits, relate to each other?
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Mapping backyard by using multiple antennas/beacons [on hold]

I'm thinking about making my own autonomous lawn mower. This is just brainstorming idea for me. Most of devices currently on sale is using wire layed or dug into the soil to determine the limits and ...
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Antenna Polarization understanding

I am trying to design a Circular polarized Antenna. We know that the criteria for a circularly polarized E-field : The E field should have to components The two components should be equal in ...
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1answer
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PEC-backed dielectric material

For the paper named "Antenna Miniaturization and Bandwidth Enhancement Using a Reactive Impedance Substrate" the statement "PEC-backed dielectric material", so what is the meaning of this statement? ...
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External Antenna connection on MFRC522

New to RFID world. I am working on a Healthcare product. One of the feature includes authentication of patients which will be done through RFID reader MFRC522. Application schematic in the datasheet ...
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Radiation Source placement and waveguide parameters for Horn Antenna

I am designing ("arranging", actually) a horn antenna for a 77-81 GHz Radar. My module has a patch antenna which can't be placed inside the waveguide for some reasons. After the patch antenna, we have ...
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1answer
44 views

can aluminum foils increase the boost the range of nfc reader?

I have been working on a project where I have to read data from an NFC tag and store the information locally. Currently I have a range for the NFC tag of about 5 cm. The tags will be present inside a ...
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Taking of E,H plane patterns

In many textbooks i have read E-plane is taken at a given azimuth where maximum radiation is observed and H-plane is taken at a plane perpendicular to the Eplane.Does it mean H-plane should be taken ...
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2answers
21 views

Ratio between RFID reader and tag antennas

If a tag's antenna (45mm x 75mm) is larger than the reader's antenna (20mm x 26mm), could this pose coupling problems when trying to read the tag? The reader functions correctly with tags similar to ...
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1answer
38 views

Can I use a Ku band satellite dish for Wi-Fi?

Satellite TV works at 18-24Ghz and WiFi at 2.4Ghz, will a T.V dish antenna work for WiFi? Diameter of the dish is about 60-90cm
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Strange shapes on the Wi-Fi module PCB

LG has this Wi-Fi module: This is a 2X2 Dual Band AC Wi-Fi / BT module. You will see two folded WiFi antennas on upper side and one bluetooth PCB trace antenna at the lower right side. I found this ...
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Unexplained differences in behaviour between U.FL-terminated antenna and SMA-terminated antenna

I would like your opinions/advice regarding an unexplained observation between a U.FL-terminated antenna and an SMA-terminated antenna. Both antennas are from the same manufacturer and normally tuned ...
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How to connect antenna into circuit properly?

For my antenna design class I am fixing an FM radio that I made by making a better antenna. I am planning on using a half-wave dipole as the antenna for the radio. The issue that I am having is that I ...
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1answer
36 views

Finding out antenna gain in 3-D space (azimuth and elevation)

I found a cross-sectional view of a patch antenna's gain below. I would like to know how can I determine the antenna's gain for every azimuth and elevation angle in 3-D space?
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Does a lithium battery make a good ground plane?

A patch antenna I'm using calls for a 50mm x 50mm ground plane under it, mostly to cut multipath reflections in the bottom lobe. Naturally, the closer to the antenna and the more conductive the ground ...
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What do we mean by spatial smoothing in 1D antenna Array?How does spatial smoothing helps us in estimating direction of Arrival of signals?

I want to know the motivation behind spatial smoothing in Antenna Arrays.Can anyone help in explaining spatial smoothing in Antenna Arrays.
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Determining whether signal meets the 12 dB SINAD voltage

The specification for the sensitivity of a certain radio receiver says: Typically 12dB SINAD NBFM for 0.15uV at 145MHz. If I understand correctly, this means that the received radio wave should have a ...
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1answer
81 views

why is it bad if a coax cable (used for antenna cable) has multiple paths to ground?

I have an Internet modem/router device connected to a 20 foot LMR400 coaxial cable which uses N-to-N type connectors to connect to a 10 foot LMR400 cable, which is then connected into an ...
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1answer
59 views

Solar panel array interference with DVB-T reception [closed]

We are looking to get solar panels installed, and also currently use DVB-T to get TV via antennas in our attic space. The solar company has suggested that the EMF from the panels/cabling will make ...
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3answers
100 views

RF loop Antenna design layout

I am designing a bioimplantable circuit for a biomedical implant. The goal is to have an extremely tiny device in a flexible substrate (Dupont Pyralux) that must be powered wirelessly. My problem ...
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1answer
59 views

Measuring the orientation sensitivity of a UHF RFID transponder, where do the deviations come from?

I measured the orientation sensitivity of a UHF RFID tag using a Voyantic Tagformance Lite RFID test device. I rotated the tag along the 3 axes using a stepper motor and a rotating table. The ...
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How does this UHF antenna works?

I have a cheap UHF RFID antenna (9dB) like this : How does this kind of antenna work? There is no dipole? Why does the "L" at the bottom left of the disc have finer passages than others? I can not ...
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Do the dipole antenna edges have earth potential or is it a closed circuit made of co-axial cable?

I understand the shape of the dipole antenna, but how is it fed so that the current only flows through one direction during the half cycle? Even in a normal pole antenna, is there a ground at the edge ...
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Does feedline of through-hole antennas have to be at the bottom?

Does feedline of through-hole antennas have to be at the bottom of the PCB or is it ok to have it on the top? I don't see why it can't be on the top but I read in Taoglas docs that it should be on the ...
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1answer
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Bigger GPS antenna better or more efficient?

I have the choice between: 1) 35x35mm GPS antenna 71% efficiency glonass, tested on 70x70 GND plane 60% gps 2) 25x25mm GPS antenna 83% GPS, 84% glonass, tested on 50x50 GND plane I have read ...
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36 views

Is it right to define ground as a pool of surplus free electrons, like a metal?

In a dipole antenna or any other pole like antenna, there is supposedly a ground on one side causing the current to flow away and towards the ground towards the feed, but if the whole antenna itself ...
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Non resonant antenna electrical model

I apologize in advance if my question is too naive or incorrect; I am still very new in the difficult domain of RF and antennas. I know that at the first order, a resonant antenna can be modeled ...
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Electric field near dynamic loudspeaker at resonant frequency

Background I am driving a cheapo 8 Ohm speaker with an LM386. The LM386 circuit is nearly identical to the one in the datasheet shown below, except Vin is AC coupled through a 10uF capacitor and the ...
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2answers
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Can I use the same antenna for GSM and RF433 MHz?

I've already designed a PCB with GSM/GPRS chip and also with RF 433MHz receiver only (without transmitter). I would like to know if I can use the same antenna for both GSM/GPRS module and RF 433MHz ...
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1answer
52 views

Will two identical antennas next to each other pickup the exact same noise?

If you had two exact same antennas next to each other, say 10cm, or even wound together. Would they see the exact same noise? I'm thinking whether it would be possible to amplify a signal by ...
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2answers
39 views

RF Design - Antenna Feed-line Parameters

I am implementing a BLE device with a chip antenna. The device has already been impedance matched to 50Ω and is ready to be connected to the feedline and antenna. The antenna datasheet has a ...
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2answers
68 views

Z=50 and Xs=0 but SWR is not 1.0:1

I measured an antenna with a VNA and differently to all other cases the SWR isn't low as expected. Here are some screenshot showing this: Similar situation, on the same antenna in the same ...
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1answer
36 views

Comb generator vs. known EMC emitter - different measurements in shielded tent vs. 3 meter chamber

I've got an EMC testing setup of a 1 meter shielded tent, and a very high gain EMC antenna. I'm seeing a phenomena that I can't quite explain. I have a known product that was tested in an accredited ...
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3answers
4k views

Do square wave exist?

If we send a square waveform through an antenna, will we get square electromagnetic waves with electric and magnetic fields looking like squares? Also, since there is an abrupt/almost jump in ...
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1answer
60 views

2.4 GHz Chip antenna layout

I am am new to RF design and I need to place a chip antenna due to space limitations. The only antenna that is easily available to me has a very weird layout. There is no physical connection from the ...
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46 views

Single-frequency AM Receiver?

Previously today, I tried to make an extremely simple AM receiver without a tuner. It didn't really work (I'm still trying to work on it), but I also tried to make an AM receiver that is tuned to one ...
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39 views

Minimum antenna separation

I am trying to design an RFID system. The transmit antennas will be placed along the length of a 12 by 3m rectangular truck container and be placed at the midpoint of the height of the container. The ...
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34 views

Planar Inverted F Antenna Printing

I am trying to get a planar inverted F antenna milled via Pcbway. I created the gerber files using CST microwave studio. I keep getting bounced back with the error: "No keepout layer(board outline),...