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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How do i find the FNBW of a main lobe using a diagram?

Looking at the graph below, i can see that HPBW of the main lobe is around 45 degrees, but when it comes to identifying the FNBW i have trouble understanding it. Reading various articles online i've ...
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How does a wifi antenna work?

let's consider a common wifi antenna (used in routers) like this: I don't understand some its basic features: 1) Is it a dipole or monopole antenna? I see only one conductor, so I'd say it's a ...
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Watt output of radio station

I was wondering how many watts an AM radio station outputs, and if I can calculate the watts on a tuned antenna by this equation: Where Win = the watts input for the antenna, Wout = the watts output ...
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Are there any special considerations for extending a UHF-carrying coax wire in a small device?

In the process of doing a repair on a mobile phone, I've tracked down a "no service" issue to an antenna lead inside the case. Specifically, it has detached from the U.FL/MMCX (I'm not sure ...
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How to match RF output of (30+j10) Ohms to 50 Ohm antenna with matching network?

I'm designing a matching network for a 2.4 GHz inverted F antenna on a PCB that I am also designing. I am using an ESP32-D0WDQ6 MCU, and reading from the datasheet, the output impedance for the RF pin ...
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Is it possible to find a private tutor teacher for electronics, or a serious course online? [closed]

I am asking here: Is it possible to find a private (paid or not) tutor teacher for electronics, or a serious course?
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Where is the antenna in this remote control board?

This is a PCB of a (radio?) remote control.
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2answers
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Electrically short antenna

I am trying to understand fully the problem with using electrically short antenna to transmit RF signals (i.e length significantly shorter than the intended wavelength). Currently my understanding is ...
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1answer
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How can I increase the range of a transmitter?

I am trying to increase the range of simple FM transmitter. Can I increase the range without changing the voltage of the transmitted signal? If this right what are some other ways?
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Why I've weak Bluetooth signal with Sim800C and how to strengthen it?

I've designed a circuit and used SIM800C module to work with its standard Bluetooth and GSM module. GSM works well, but its Bluetooth has weak signal, which I've to stick my phone to the board. In ...
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1answer
97 views

Chip antenna too good to be true?

I have the following setup: Very small PCB - 25mm in diameter that hosts chip antenna; I feed directly into antenna matching network with about 7.5cm coax via ufl connector; There are no other ...
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Should RF output of (30+j10) Ohms be matched to 50Ohms for antenna matching network?

I'm designing a matching network for a 2.4GHz inverted F antenna. I am using an ESP32-D0WDQ6 MCU, and reading from the datasheet, the output impedance for the RF pins is (30+j10) Ohms. (DATASHEET in ...
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How reflection occuring in antenna fed by transmission line affects performance?

Transmission line considered is lossless. Basically the configuration is simple. For transmitter side : a non ideal source (can be voltage current or power) feeding a transmission line (TL1) with ...
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How does the thickness of a dipole antenna affect the gain and the field strength?

I was asked this question on an exam and I couldn't answer it. I've searched the web and looked in my books but I can't find any information about gain and field strength vs. dipole thickness. I know ...
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What's the difference between Ku band Satcom vs UHF Satcom bands?

Assuming that they are both used by the military. What are the basic difference of purposes?
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71 views

Is interleaving used in MIMO?

Correct me if I'm wrong, this is my understanding of MIMO: Is this how MIMO is able to increase data rate?
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Microstrip Patch Antenna Design

I am Awais and I want to design a dual-band antenna in CST studio. My requirement is to design at an operating frequency of 2.45GHz and 5.8GHz. The problem is when I simulated, it was resonating round ...
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can anyone point me towards the math behind biquad antennas?

I've looked everywhere for the equations to build a biquad antenna. Calculators are nice, but I want the math. Just point me In the right direction since I've had zero luck on Google.
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How does MIMO increase data rate?

I understand how using multiple antennas helps improve reliability as it combats multipath propagation through redundancy. But how does using multiple antennas increase data rate?
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What is formula for radiation resistance for folded dipole antenna?

This may look like a question that could have been asked on Google. But every thing I searched show me formulae for feed point impedance of folded dipole and not radiation resistance.
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1answer
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Electromagnetic coupling on printed circuit board traces

When I applied the following damped signal in the proximity of my product (the magnitude is around 10 kV and the frequency is around 400 kHz) through a cable of 4 meters, the microcontroller sees a ...
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2answers
67 views

More on standing waves in a dipole antenna

I have a background in physics and I'm trying to get into antenna theory for a personal project. I had some questioning about standing waves, and reading Standing waves in Dipole antennas and the ...
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1answer
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Antenna Radiation Patterns Explained

Been struggling to find information that I find to be obviously missing on how to interpret antenna radiation patterns. For example have a look in the datasheet for my chip antenna. I can understand ...
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1answer
33 views

Does an alternating current have surface charges associated with the current charges?

As alternating current passes along a wire: Different charges are pushed to the surface in response to the current charges and form an excess electric field, leaving the interior wire neutral. ...
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1answer
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Regarding PCB IFA microstrip antenna mirror image on ground plane hole areas

This is regarding the adjacent mirror image formed over the ground plane by a PCB antenna during operation. Take the first image of the IFA with the ground plane highlighted in yellow on layer 2, the ...
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2answers
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433 MHz Antenna - Balanced Dipole + Balun?

I've got three 433MHz receivers (all the same type) and I would like to increase the range on them (by which I mean the physical distance that the receiver can detect the signal from the transmitter). ...
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1answer
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AVX M830120 SMD GPS antenna problems - cannot get GPS fix on a prototype board, strange S11 measurements

I’m struggling with AVX M830120 SMD GPS antenna in my project. I have used it in prototype board, did PCB layout more or less according to datasheet, and couldn’t get GPS fix no matter what I tried. I ...
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What type of antenna is this?

I was hiking in the mountains when I stumbled upon this antenna. I had no connection throughout the mountain until I reached this antenna. I noticed that it said on the metal. "Alarm Actuated ...
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How to Use a 2.4GHz Chip Antenna for ESP32 Design

I am designing a circuit board that will use a 2.4GHz SMD chip antenna from Molex. I am a n00b/amateur at PCB design so forgive my ignorance - does it work nearly the same as how a PCB antenna works? ...
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1answer
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Having trouble with an aviation-band receiver

I finished assembling an aviation band receiver that I bought online. I thought it would be good project for my resume, as I am an electrical engineer major at a University in California. I read the ...
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6answers
113 views

Why are transmitting antennas generally larger than receiving antennas?

The reasons I can think of are transmitting antenna has to be more directive also larger length will imply larger power and thus will help compensating for losses. But on contrary if receiving antenna ...
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1answer
51 views

What connector is this? (Inside a wifi modem)

I was about to attach an antenna to my 4g modem and thus trying to identify which connector is there on my modem board and i found this connector (4 of them, 2 for 4g and 2 for wifi). I tried ...
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1answer
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How to calculate the properties of spiral antena?

I noticed some articles about analysis of Archimedean spiral antena. My understanding is that the antena of such type is a compact one and it allows broadband performance. To be more precise I'd like ...
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Is it possible to add gain to a dipole antenna without changing its radiation pattern?

In every reference book I've seen, an electric dipole antenna has basically a donut pattern, and as things are added to increase the gain (directors, reflectors etc) the pattern changes. I've always ...
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Dipole antenna resonance frequencies

let's consider a simple dipole antenna of length L. The following picture refers to a half-wave dipole: In general, at different frequencies, it's known that different modes are possible. Precisely, ...
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Amplifying signal strength of a u.fl antenna

I have a mini pcie wlan card which uses a mini pcie to pcie x1 adapter card. The adapter card has 2 threaded male connectors which look exactly like conventional rg6 but smaller. Those lead directly ...
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1answer
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Difference between IRS and phased array/reflectarray

just wondering out of curiosity the difference between intelligent reflecting surface (IRS) and more traditional antenna arrays such as phased array and reflectarray? From the surface it looks a whole ...
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GPS patch antenna pcb design

could you please review my layout? It's the top side where the antenna is actually placed. It's bottom side, here I've placed a matching network, LNA (U5)2 and SAW (FL1). The length of the trace ...
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What is the required ground size for the S2LP RF module?

I'm designing a four layer board with an RC-S2LP-868-HA RF module which has a little helical antenna. I have two question about that. First, how do I calculate the required ground size for the RF ...
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1answer
32 views

GNSS antenna properties

GPS has three seperate frequency bands which are L1, L2 and L5 while Glonass has two seperate frequency bands including L1 and L2. Also Galileo has three frequency bands named as E1, E6 and E5. I ...
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52 views

Why does an LHCP (or RHCP) antenna reject RHCP (or LHCP) signal?

I have no background knowledge about antennas. I am trying to intuitively understand how an antenna transmits and receives a circularly polarized (CP) Electro-Magnetic (EM) wave. From the knowledge, ...
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What is the benefit of dual polarization in radio communication?

Why are some PtP antennas and radio units connected by two feed lines -- one for horizontal polarization and one for vertical polarization? I know the difference is in the orientation of the electric ...
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What is the meaning of dBi?

When we say, for example, an antenna has spec of 22 dBi; Does it mean that its power is 22 dB stronger for any point at fixed direction than if it were to emit spherically?
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FM antenna isolation

I want to connect a car antenna (FM radio) to a phone's jack sleeve to provide a good antenna signal to the phone (for its FM radio part). As the car might add some supply DC to the antenna, I decided ...
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1answer
46 views

SMD antenna connection to an RF module

I want to design my first wireless device. I want to use an RF module called RC-S2LP-868. My problem is that I don't know how to connect an SMD antenna (ANT-868-HESM) to that. There is a small SMA ...
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3.3V GPS with 5V active antenna bias-tee

I'm building a multipurpose MCU + GPS device and doing breadboard experiments at this stage. The Ublox Neo7 GPS IC is on a breakout board at 3.3V. The board supplies about 3.1V to the antenna which ...
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Help identifying mysterious communications tower

There's a tower near my house that I thought was a cell tower, but I noticed it's not registered on the FCC map. Can anyone help me ID what type of tower this might be? I was thinking it was a ...
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2answers
1k views

WiFi antenna understanding, which is 2.4, 5 GHz

My USB WiFi adapter has two antenna connectors, I have a lack of knowledge of these connectors, few questinos: how to check which connector is 2.4/5 GHz or both are 2.4/5 GHz at the same time? comes ...
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Is there a way to determine which antenna connector is for which radio on a cellphone?

I have a cellphone mainboard from a Sony Z Ultra: There are 4 antenna connectors on the board, 3 of them unconnected (marked with red dots). One of them is connected (green wire), that might be the ...
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1answer
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Loopstick (ferrite rod) antenna circuit model

A ferrite rod antenna circuit equivalent is usually given as so: The numbers are made up, I didn't calculate the exact C you need to have to make it resonate at 1 MHz. Here's a slightly more ...

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