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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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A7 GPS module active antenna [on hold]

Can I connect an active gps antenna to the module directly, or should I connect power supply to antenna separately? My antenna is like image: DC voltage: 2.7~5v LNA Gain: 25.2dB DC Current: 6~...
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30 views

AM Radio aerial problem [on hold]

I have a Mazda Utility vehicle that has a extendable aerial on the 'A' pillar and it is held onto the roof with two screws. When I remove the screws and pull the aerial slightly about 25mm (1 inch) ...
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34 views

GSM antenna connection from the phone does not make sense

I recently came across a phone (Samsung Galaxy Grand Prime SM-G530f) with trouble getting any network signal, I did some troubleshooting and ended up finding out that one of the pin(the GSM pin) to ...
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Effect of with and without ground plane on gain and impedance bandwidth characteristics of microstrip patch antenna

May I get an explanation of how will the gain and bandwidth (either will it become a narrow or wideband) characteristics of a microstrip patch antenna with and without ground plane be? What's the ...
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1answer
20 views

XBee Pro Antenna Options - do the U.FL antennas have better range than the chip or micro pad antennas?

Logically the U.FL dipole antenna will have better range than the other two options, as it's a larger antenna, but is this actually true? How do the three antennas perform in relation to each other ...
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1answer
36 views

ADC wire is picking up noise from cellular antenna [EMC]

I have a 5 wire micro jst cable with a line for ADC readings from an IR sensor that is picking up interference from the cellular antenna of the microcontroller. Will I be able to reduce this noise if ...
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1answer
39 views

Why do two antennas have to have the same polarization?

I have a linear horizontally polarized transmitting antenna and a dipole antenna, polarization mismatch losses can be approximated by 20log(cos(x)) where x is the misalignment angle. What is ...
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82 views

What antenna is this?

I just disassembled an external FM antenna designed for an old Asus laptop. I expected to find some circuitry and a monopole or some other simple antenna. However, what I found was the antenna shown ...
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1answer
28 views

Reconfigurable antennas at base-station

Can reconfigurable antennas be used at base-stations and cellphone towers? I read that MIMO antennas are used at base-stations for 4G systems (and will be used for 5G). Are these antennas ...
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27 views

Creating a balanced dipole from two monopole chip antennas for use on small PCBs

I'm trying to use a monopole chip antenna on a PCB much smaller than the one recommended in the datasheet. I am wondering if I can get away with a much smaller board by using two monopole antennas ...
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2answers
68 views

I don't know how to choose an adequate antenna

I need to choose an antenna for a long range free space communication (~10km), and I currently have a receiving antenna, but I don't understand enough to be able to pick an adequate emitter. The ...
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1answer
23 views

Equivalent Series Resistance of 13.56 MHz RFID Antenna

I am designing a system that uses the MFRC522 by NXP Semiconductors and I am having a bit of difficulty designing the antenna. NXP provide an antenna design guide under the application note AN1445 ...
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1k views

What is the “maximum power” of an antenna?

I was reading the datasheet of an antenna and I came across the parameter "Max. Power (total)", measured in Watts. What does this stand for? Can it be measured to check that the datasheet is right?
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1answer
101 views

Designing 60hz antenna to detect electric field

I am working on designing an antenna to detect 60Hz electric field. I came across the microstrip antenna being used to detect the field. Before designing the antenna I wanted to maek sure this is the ...
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25 views

Yagi-Uda antenna - energy flow density calculation

There are given two, identical, parallel, short dipoles perpendicular to the OX axis connecting their centers, located at a distance of λ / 4 and supplied with a phase shift of π / 2 (figure below). ...
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1answer
34 views

Difference between a flared and not flared rectangular waveguide antenna

Someone can explain to me the difference in terms of performance between a flared rectangular waveguide antenna (precisely a pyramidal horn) and a not flared rectangular waveguide antenna? In horn ...
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1answer
14 views

Friis transmission equation (log scale calculation)

I am trying to understand the Friis transmission equation. My scenario: I consider transmit antennas (\$T_x\$) and receive antennas (\$R_x\$) at a distance R [km]. f [GHz], \$G_{T_x}\$ and \$G_{R_x}\$...
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1answer
28 views

4g transmit from a tv antenna to an indoor antenna

We have a TV antenna on the roof, works on 5-2600 MHz. Its cable runs from roof to my room, connected to the TV. I am wondering if I could transmit 4g signal using another antenna, by connecting a ...
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3answers
55 views

Why does antenna tuner in crystal radio use capacitor and an inductor?

I know that antennas can be capacitive or inductive depending on the relation of antenna length to the \$\lambda\$. I know that crystal radios use both antenna and capacitor for tuning and I don't ...
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29 views

nRF24L01+ radio pcb trace matching components for SMD Antenna

I am trying to design a pcb layout with the nRF24L01+ chip. The documentation seems to cover nearly everything I needed to know, but with a small thing left - the antenna. I would love to use an SMD ...
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1answer
38 views

Have you ever fried a wi-fi router by leaving it to work without its external antennas?

I wonder if a wi-fi router can be damaged if its external antennas are unscrewed? Have you ever damaged such a router leaving it to work without antennas, like this: Source I know that there are ...
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2answers
44 views

Impedance-matched antenna with an extra capacitor

I'm looking at the a schematic for an ESP8285 module, and I am curious about what they are doing with the antenna. The module is the PSF-B85 (by ITEAD: the version with a chip antenna). The antenna is ...
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1answer
52 views

How do I figure out the ohms of an antenna?

I'm looking at the CZE-05B FM transmitter and in the manual it states the output load is 50 ohm and I need an 50 ohm antenna. So my questions are is this antenna 50 ohms? https://www.ebay.com.au/itm/...
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Designing NFC PCB antenna in multi layer instead of usual 1 layer antenna

I'm working on a new NFC reader board with serious limitations in dimension of the board. This cause smaller antenna coil, which affect on range and power of antenna. My boss suggested to design coil ...
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1answer
31 views

Can I find the loss tangent of a substrate if I know the thickness of substrate and its relative permittivity?

What is the formula to calculate loss tangent for a substrate with relative permittivity 4.4 and height 1.58 mm? I need the value for designing a PIFA with 35-micron copper ground conductor.
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2answers
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How to fix this wifi FPV antenna

I do not know much about antenna's. A wire broke off of a Wifi antenna, being part of a video transmission unit of a quadcopter. The short grey colored wire on the right side of the picture broke off....
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1answer
34 views

Receiver Antenna Gain

How is gain defined for a receiver antenna? If we look at a radiating antenna, there is a Pin, and the gain in a particular direction would be the radiation intensity Ur, divided by the radiation ...
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1answer
52 views

Manufacturers' recommendations for ground plane for GPS patch antennas

I see requirements for specific ground plane sizes in many GPS antenna datasheets, but I also see many devices that ship with significantly smaller ground planes. Do these integrators know something ...
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1answer
34 views

Antenna polarization and antenna directivity are the same?

I'm working on an RFID project, and looking for information about the antennas that I have to use, I have the following doubt: Antenna polarization and antenna directiivity are the same? Thanks!
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1answer
28 views

The meaning and role of the phase in antenna measurements with VNA

VNA measurements of an antenna return Z, RL, Xs, Rs... and also phase. I usually check Z=50 and Xs=0 to reach the max Return Loss and the lowest SWR 1.0:1, without having care of phase values. ...
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56 views

What exactly is Electrical length in Radio Frequency or EM waves

What is electrical length in detail? Why is it so that 1/4 wave , 1/2 wave dipole antenna works properly and not a full wave antenna? What is the role of electrical lengths in degree?
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1answer
69 views

What is the precise meaning of “matching impedance” for an ultra-wide band antenna, and how to do that?

Well, actually, I'm not sure I really understand what is the meaning of matching impedance, even for an ordinary antenna, but I can figure out the following: if you send a signal to the antenna, then ...
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1answer
58 views

what is the good antena length for 433Mhz modules used for low distance domestic usage?

I want to use a low cost 433Mhz module for low distance domestic usage, but I need to solder an antenna , (there is a place for that on the reception module), to get a better signal across my walls. ...
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2answers
88 views

Receiving power from antenna (Homework)

The question: "At a carrier frequency of 2 GHz, assuming a transmit antenna gain of 3 dBi and a receive antenna gain of 0 dBi, calculate the line-of-sight received power at a distance of 100 m from ...
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3answers
115 views

Voltage gradient across an antenna (and how it drives an AM radio)

Edit: I was interested how is voltage gap maintained across an antenna. It seemed to me that an antenna might be like a wire where if there's a voltage at the top, the same voltage would be at the ...
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0answers
33 views

yagi antenna gain formula

is there any specific formula to calculate yagi-uda antenna Gain? i know that The Gain of Yagi Antenna depends on length of antenna array and do not depend on number of directors used in the design , ...
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52 views

Should the antenna be 'better' for the transmitter or receiver?

I intend for this to be a general/conceptual question that could apply to any wireless communication setup, however I will use a specific example to make things easier. For my example, I'll be ...
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3answers
1k views

How can I make Bluetooth (2.4 GHz) reception area narrow and controllable?

There are some Bluetooth modules available on the market, like the cheap HC-05 for 3 or 4 USD delivered. This one mentioned has an internal PCB antenna which I guess has a toroid-like radiation ...
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1answer
44 views

When deforming a resonant circuit into an antenna, why can we cut the inductor in half?

The working principle and fields of an antenna can often be shown by considering a parallel LC circuit. The plates can be moved to opposite ends and the inductor can be stretched out, both of which ...
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2answers
425 views

Does an electrical outlet radiate EM waves? [closed]

Please consider all cases even with a tiny values. If plug two separated wires to each terminal of electrical outlet, like shown, will it radiate em waves? ...
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2answers
93 views

Will this receiver work?

I'm just a beginner, trying to understand an antennas and transistors as an amplifier, I'm studying, please correct me. Here we have a voltage source, PNP bipolar transistor emitter-base-collector ...
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0answers
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CST Studio Space State Matrices

I am new to using CST Studio and I am trying to figure out how to see the state space matrices (A,B,C,D) of a designed antenna to describe its radiation pattern in other software. Any help on the ...
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2answers
62 views

Why voltage source has been connected via inductor at the output of LNA?

I have been reviewing the schematics of LoRaWAN Gateway designed by Microchip (Page 48). The output of the LNA has been connected to voltage source via inductor. ...
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44 views

Inductor for a GPS active antenna

I have been testing the GPS / GPRS development module A9G, Aithinker which uses an active GPS antenna, according to the schematic reference diagram, the value of the inductance is 82nH: The question ...
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8answers
6k views

Why is 50 Ω often chosen as the input impedance of antennas, whereas the free space impedance is 377 Ω?

In order to efficiently deliver power to a different part of a circuit without reflection, the impedances of all circuit elements need to be matched. Free space can be regarded as a further element, ...
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4answers
109 views

Does the EM radiation from AC power lines propagate through air or is it fixed around the line?

Because of the AC current flow, there is a changing magnetic field around the conductor, that in turn induces a changing electric field and vice versa But does the EM radiation get "loose" from the ...
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2answers
159 views

Can I use more than one antenna with a radio module (say rfm69) and switch between those antennas electronically, say by a transistor

I need to know the approximate direction of the radio signal coming to my module, and I have to use very simple hardware and software for this. (Just a microcontroller and one module) What came up ...
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1answer
43 views

Removing the imaginary part of input impedance of a Monopole in HFSS

I am building a Monopole in HFSS for my project. Its structure is shown here : The input impedance at the desired frequency is : Now i need to eliminate the imaginary part , so that the voltage and ...
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2answers
70 views

Analysis of an LC circuit antenna

I want to analyse a parallel LC circuit in terms of inputs and outputs as I am studying them in the context of using them as a tuned antenna. However I am unsure of where to identify the inputs and ...
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1answer
32 views

How to calculated weighted gain of antenna?

I have this test specification for testing antennas and it defines weighted gain as follows: The weighted gain is calculated from the transfer function (S21) using only the gain values within the ...