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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Does antenna thermal noise matter if noise power is higher?

I'm working on designing a radio system for CubeSats and I want to make sure that the sensitivity of my receiver is as high as it can be. I'm trying to understand what parameters are going to set the ...
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Resonant frequency of copper tape

I understand that if I want a piece of wire to act as an antenna the length of the wire should be at least λ/4. I wanted to know what would be the equivalent if I used a piece of copper tape instead ...
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Antenna Trace Impedence matching

I'm developing a wireless board. Datasheet suggests to use an external UFL antenna 50ohm Trace impedance. UFL socket which I selected is having 50 ohm impedance. So should I offer 50ohm trace ...
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How to build a safe antenna switch and how to simulate loss of reception?

Problem : I'd like to run the following test routine with an LTE router: cause a loss of signal, as if the router entered a tunnel remove the signal obstruction, as if the router just exited said ...
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How to decide RFID tag antenna inductance?

I know how to calculate the antenna inductance of a given RFID tag antenna but how do I decide what value of antenna inductance is needed for the design?
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Pi matching off-board antenna with module pigtail

I have an Iridium 9603 satellite modem integrated in a project and would like to tune its antenna feed line using a pi matching circuit on my carrier PCB. What's unique about this situation is that ...
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GPS Active vs Passive SMD antenna

I'm designing a tiny wearable device that is characterized by a plastic case. It contains the PCB and the battery (Lipo). I'm struggling a lot with the GPS antenna because I must use a small SMD ...
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What do I need to connect an R-SMA male to a standard coaxial male? [closed]

I have a router that has the following type of pigtail connector soldered to the board which I believe is an R-SMA male coaxial cable. I'd like to connect it to a standard male coaxial cable that's ...
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Antenna separation distance in Doppler radar

I'm wondering if there has to be a specific antenna separation distance based on wavelength in a Doppler radar. I'm building the above setup (all antennas are equal size,) and I'm wondering if there ...
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How does one test an AM antenna matching network?

I'm lost. I need to test two AM matching networks. I was not given training and I'm a newborn compared to every other guy in AM Radio out there. I do own a osciloscope with Bode plot generator but I ...
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1 answer
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Could I use aluminum foil as a ground plane for 1.4 GHz antenna?

I'm currently attempting to make a radio telescope that works at 1.4 GHz. Would household aluminum foil work as a ground plane? I saw someone asking the same thing for a 900 MHz antenna and I was ...
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Using SWRA117D 2.4 GHz antenna on a large board

I've added the board image. There is one ESP32-C3 on a 2 layer FR-4 board. My question is, how much I'm compromising with the efficiency of the antenna by placing it on a ~52X85mm board considering ...
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Is there any difference between antennas applications?

I'm thinking of adding LoRa module to the PCB I designed, and I chose an antenna. NN02-201 The reason I chose this antenna is because I can easily find it in the country I live in. However, LoRa is ...
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RF impedance matching other than 50 Ω

I am working on an VHF down-converter using the SA602. The RF input impedance to this chip is 1.5 kΩ. I understand that hooking up to most antennas will require a 50 Ω matching network. However, for ...
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1 vs. 2 balun(s) on extension cable

I am quite new to SDR and RF learning and experimenting. I am trying to build an extension cable to relay an RFID signal (125kHz) to various distances (2,5,10m). I am using 2 identical antennas at ...
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How to connect the VNA to RF transmission line for antenna tuning?

I am working on a 2.45 GHz(Bluetooth) project. the design has a Chip antenna with 50 Ω impedance trace to connect antenna and chip. I intend to tune the antenna impedance using the Pi network using ...
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How do current and voltage work in a dipole antenna?

I don't know if I understand how it works. For example, does it mean that on the right side there is Vmax, for example 5 V, and on the other side there is Vmin = 0 V? Let's say I have Vin = 5 V. And ...
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Is a copper plane a good antenna?

It is said that the size of a 1/4-wave antenna is approximately one-quarter of the wavelength of the desired frequency. I saw also somewhere that it can also be longer than 1/4 and it will also ...
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Using antenna instead of an AC source on the circuit diagram

Here's an LNA circuit I found on google: Can I replace the AC source with an antenna?
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2T2R with two antennas

Regarding the 2T2R, the device should have two transmitter antennas and two receiver antennas in order to double the data rate. However, as I see different devices, the 2T2R has only two antennas, and ...
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Impedance matching antenna, bandpass filter, SDR setup

I have the following setup to receive NOAA APT satellite images at 137 MHz. It is a DIY v dipole antenna and bandpassfilter. I measured the impedance of the antenna with a network analyzer. It is ...
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Grids to make antennas more directional

I am designing a parabolic antenna for a radar project. The frequency range I had chosen should be from 0.4 to 1 Ghz, with a gain of about 15 db. This antenna is only for receiving, but I found out ...
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3 answers
354 views

Monopole antenna: does current flow in loops?

I've been wondering for the longest time about how a monopole antenna (like the one in a typical FM radio) can work without offering a return path for current. I have a hypothesis, and I'd really ...
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1 answer
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Ground plane radials not improving monopole design

I have a transmitter setup from my router like shown below. The backplane is made from cardboard and has an RPSMA male wire held up in the middle. It is attached to my router. Goal: design a monopole ...
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Equipment with two 2.4GHz radios

Never even thought about this, RF is not exactly my field. However, I need two Bluetooth modules (one is classic, the other low energy, I can't use a single module) on the equipment. I have access to ...
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How can I assign "excitation" to LPDA in HFSS?

I have been a new user of Ansys HFSS electromagnetic simulation software. I have designed a log-periodic-dipole-array (LPDA) in the HFSS but I could not understand how to assign excitation to my ...
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Return loss of antenna

I was borrowing a Field Fox VNA to look at some antennas and was trying to verify what I was seeing with a known antenna. What I am confused about is the return loss graph of this antenna from mouser ...
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Why do some GPS modules in smartphones have two or more antennas?

Some GPS modules have only one antenna, but some of them have two and more. For what? Are they made for different frequencies and ranges?
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At which point do we take the value of impedance to tune an antenna?

I am a beginner in antenna design and tuning. I want my antenna to have a resonant frequency of 2.45GHz for low-energy Bluetooth communication, and I want to know what to consider for the matching ...
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1 answer
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How to explain mathematically 2.4 GHz and 5 GHz WiFi coverage and maximum range?

The question is why 5 GHz has less coverage and more susceptible to attenuation in long range? How can we mathematically represent how many devices can be covered?
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How to correctly model a receiving antenna?

I want to amplify the signal received by an antenna for GSM signals. I am currently modeling the antenna as a 900 MHz sinewave generator and a 50 Ω resistance in series with it. However, I doubt this ...
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Effect of small length impedance discontinuity in a transmission line

Consider this arrangement of a radio, a long coax cable, a small length of "random" cable and an antenna. The radio, the coax and the antenna all have the same impedance, but the random ...
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From its electromagnetic field, what makes a too short antenna capacitive, and a too long dipole antenna inductive?

I know that at a given frequency and therefore wavelength, a dipole antenna that is too (electrically) short looks capacitive, and one that is too long looks inductive. I can see it on the Smith Chart,...
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Can I extend the range of this 433.92 MHz gate opener by soldering a copper wire to it as antenna?

I have a 433.92 MHz gate opener remote that I would like to be able to control from my phone. In order to do this I have soldered a relay to one of its buttons, which I already have means to trigger ...
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What makes difference in antenna gain pattern?

Let’s assume that we have a cavity backed antenna which has half-omni coverage, or call it unidirectional. We know that making it more directional will cause narrow 3-dB beamwidth, so above the ...
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1 answer
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Why are there two different charges on a patch antenna? How are these charge distributions formed?

If we apply an AC signal to a capacitor, we can see only one type of charge on an individual plate. If we apply an AC signal to a patch antenna, there are two different charge distributions on the ...
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3 answers
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Common base amplifier - no gain

I am trying to amplify the signal of a half wave resonant dipole antenna that picks up broadcast FM (88MHz - 108 MHz) using a common base topology 2N2222. I am trying to use an air core 1:1 ...
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Help with the design of a RF PCB transmitter

Edited with previous suggestions I work for a company that builds (redacted for privacy), and a big company lent us a special GPS anti-jamming device, and I am in charge of implementing and testing ...
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Antenna requirements, transmit vs. receive

This question is an extension of this question: Are antennas specified for a certain frequency? I've heard that receive requirements for antennas are much more lax than transmit requirements. From ...
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Are antennas specified for a certain frequency?

"LTE 868 MHz Antenna" Why does 868 MHz stand for? Are antennas specified for a certain frequency or is it necessary for something like input type? For example, I want to transmit a 40 MHz RF ...
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Can a wifi device be inductively coupled to its remote antenna?

I’m developing an electronics device that will be towed underwater and which needs to transmit data to the surface. Since RF works poorly underwater, I’m tying to extend the underwater device’s Wi-...
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3 answers
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Effect of antenna direction on antenna gain

I'm studying antenna theory right now, and I have a question about the effect of antenna direction on antenna gain. My assumption of the antenna direction is like below: Since the Rx antenna cannot ...
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Is the ground plane in patch antenna used as a reflector? If so, how does the distance between ground plane and patch affect the reflected signals?

For a reflector to work it should be placed quarter wavelength away from the source so that waves reflected back from the ground plane are in phase with the waves being generated and superimpose. In ...
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What is the difference between sleeve dipole and patch antennas, apart from ease of manufacturing and low cost? [duplicate]

Why are patch antennas used instead of dipole antennas? If we want our dipole antenna to be more directive ,we can add a ground plane that acts as a reflector or print the dipole on a substrate to ...
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Why are patch antennas used instead of planar dipole antennas?

As far as I know, the major advantage of patch antenna over dipole antenna is its directivity. If the planar dipole antenna can achieve the same directivity then why do we use patch antennas? Are ...
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Can I use a 5G antenna on my 4G router and get 5G speeds or do I need a 5G router [closed]

I have a Huawei B535 4G router at home. The SIM card sitting in it and the subscription also supports 5G. Will it be enough to just add an external antenna like this one: https://triax.com/shop/en/o5a-...
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Why is the charge distribution of printed dipole antenna different from patch antennas?

Why in planar dipole antenna current is perpendicular to the feed while in patch antenna the current is parallel to the feed line? Is the direction of current dependent on the input supply terminals? ...
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A question on radar cross section of rain by using radar reflectivity factor

The question is one of the past exam papers of the RADAR 1 course given in TUDelft, unfortunately, solutions are not provided to the past paper yet. The question: What will be the radar cross-section ...
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Confused about chip antenna schematic and copper/GND from examples

I want to use a TDK chip antenna (ANT016008LCS2442MA1) on my board. There are two (design notes datasheet) technical documents, but they contain little useful infromation. My questions are: ...
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Receiver antenna design for reading PIT tags implanted in snakes and reptiles

I am talking to a local conservation outfit trying to replace active implantable radio tags with passive PIT tags (I do not know who the manufacturer is). These active tags are really tiny glass ...
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