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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43 views

Antenna connector placement

I am currently redesigning a PCB utilizing the Xbee 868 Mhz module with external antenna connection on the pad ( https://www.digi.com/products/embedded-systems/digi-xbee/rf-modules/sub-1-ghz-modules/...
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Is there a difference between read range and read speed/sensitivity in LF RFID applications

If I want to read 125kHz tags but my antenna oscillates at 130kHz, read range will suffer given that the antenna has a low enough Q-factor to still excite the tag at 125kHz. My question is, is there ...
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Implementing a TI antenna design on an existing PCB

I'm currently working on a PCB that processes certain sensor measurements. These measurements are then periodically transmitted over the LoRaWAN network (868MHz). I'm using an RFM95 module with an SMA ...
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What are these wiry protrusions on a TV antenna?

This photo shows part of a large antenna assembly which has a series of thin wire protrusions: (Source) This antenna is apparently used for TV transmission. What are those protrusions for? I'm ...
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56 views

How do you make an antenna with length much greater than the wavelength work?

I've read that antennas work best when their length equals 1/2λ, so how does one make an antenna that is 3/2λ, 2λ, 3λ, etc. work? How do I calculate how much energy I am losing compared to the 1/2λ ...
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57 views

How to draw spiral in altium designer?

I need to draw this pinwheel antenna pattern in altium designer. But I have no idea how to do it (drawing spirals) with altium equipments. Do you have any suggestion?
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RF Jumper at 2440MHZ

I need a series component to isolate a 2440MHZ antenna for testing purposes-- it can either be a a high quality 0402 RF capacitor (Johansen) or a zero ohm resistor. The series component will remain ...
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82 views

How do metal pipes amplify radio time signal?

I ran into this YouTube video on how you can amplify the signal for your radio controlled watches: https://youtu.be/wI4FwQMCN9w In short, the guy in the video said he stumbled on a way to amplify the ...
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Radiation Pattern Intergration method for calculating Antenna Radiation Efficiency

I need to calculate Radiation Efficiency for my customized Antenna simulated using CST software.The sampled data of cst simulated radiation pattern need to be fed to the formula as mentioned below $$\...
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What's the purpose of SMA antenna connector grounding? Can I just use a copper antenna with no grounding?

I'm looking at a schematic which includes an SMA antenna connector. I'm wondering why this connector needs grounding and whether a simple copper wire without grounding can be used instead Would I be ...
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How do i make an amplifier for VLF with LM328 and BC547

i have a lot of passive components and some lm324, 2n2222, 2n3904 and bc547, how do i make a VLF amplifier to use it between an antenna and a microphone jack? i tried a darlington transistor, the ...
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Antenna Impedance Matching, 0 Ohm Response

I'm currently trying to match some SMD antenna breakout boards. These boards have one type of SMD antenna, footprints for an SMD pi network and a 50 Ohm cable as connection to my VNA. Now the problem ...
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Understanding Dipole vs Commercially available antennas

I'm working on a project involving RF. I have a pretty good understanding of "HAM Radio" style RF engineering, but not at a professional level. I'm trying to find a commercially available dipole ...
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Passive RFID design assistance

I am looking for the correct RFID tag/reader system for my design. The general block diagram of the system is above. The requirements for the system are as follows: Passive tags of some form and an ...
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44 views

S parameter meaning

I have designed a rectangular patch antenna and have tested it. From the results I noted a value of - 25dB on the S11 parameter graph. The - 25dB is also at my resonant frequency of 915MHz. Is this a ...
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37 views

Pig tail vs SMA pcb mount connector

Is there any difference in applying a 50-ohm female SMA PCB mount connector to an antenna as opposed to a pig-tail connector to a microstrip patch antenna? The difference is in terms of the ...
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Can I use a 2.4 GHz antenna for 900 MHz signal?

I have a 900MHz LoRa device that I want to attach a more directional antenna to. I have a 2.4GHz corner reflector sitting around. I was wondering if I can replace the current omnidirectional antenna ...
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52 views

Covering PCB antenna with lacquer

In my project, I use ESP-12F module which has exposed (no soldermask) plated PCB antenna included in design. However I want my PCB to be waterproof and cover whole thing with waterproof lacquer. My ...
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Active RF Antenna power PCB layout: where to place the inductor for a bias tee?

I have an active RF antenna that is powered through an inductor in a bias tee network. How should I draw it on PCB layout? I have 3 ways to do that. In these layouts, up is capacitor, bottom is ...
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How can I tell if an antenna is a dipole antenna

Background I'm trying to select an antenna for an FCC/IC-approved cellular module, SIM7000A. Apparently, to meet IC modular certification, you need to select an antenna which has a) equal or less ...
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50 views

Multiple independent antennas on same PCB

Is it feasible to use multiple (e.g. 2) independently transmitting antennas on the same PCB (e.g. 5cm x 5cm) operating in the same band (e.g. 2.4GHz), though on different "frequency channels"? I'm ...
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RFID reader technology

Hopefully this isn't too broad of a question, I will narrow it down the best I can. We need to add RFID tags to feeders on our pick and place machine, to determine that they are loaded into the ...
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28 views

Orientation of Loop Antenna (receiving mode)

I have done some measurements through a loop antenna similar to that shown in the following picture (all the informations included do not refer to my antenna, it is a picture used only to show its ...
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Slots for Dual Band Patch Antenna

I'm using CST Microwave Studio to design a dual band GSM (900 and 1800) patch antenna. I understand that I have to create slots to make it multi-band, but I'm confused as to where to place the slots ...
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Adhesive for FR-4 substrate

I would to know what sort of adhesive I can use to stick 3 FR-4 PCB's together? Back to back. These PCB's measure at 8 by 8 cm. With a single FR-4 substrate thickness at 1.6mm. The reason for ...
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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. My question is whether all these small circle coverages exist at ...
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Have trouble designing antenna coil for chip receiver

I'm trying to wind a 125khz rectangle coil antenna for the AS3933 receiver chip. I calculated inductance using this calculator where parameters were: Loop Width:20cm Loop Height:14.5cm Wire Diameter:...
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70 views

Length to make magnetic loop antenna/probe for 1.6GHz?

I'm making a near-field probe to to search for GNSS (GLONASS) blocking signals on my PCB. According to http://www.eryptick.net/unisold/loop.html the wire length for a loop should be 1/3 the ...
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How does the external antenna in ESP 8266 modules work?

I want to test the downloading and uploading speeds from various antennas of my choice via an ESP8266 microcontroller. I came across this design which I was planning on using for this. This would be ...
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Using external directional antennas with 802.11ac MIMO / beamforming

I would like to add external directional antennas (Yagi or panel with ~30˚ horizontal/vertical beamwidth) to an 802.11ac router running DD-WRT. This is for an outdoor, field application where: ...
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Geometric spreading of an impulse antenna

I am new to radar and curious about the geometric spreading in free space. I set up an air-coupled antenna about a half meter above the ground, with a large PEC on the ground. Then I adjusted the ...
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PCB with 5 Pluggable RF modules and 1 LTE puggable module - will it cause issues for reception at different antennas?

I am designing a prototype PCB which shall have 5 pluggable RF modules and one 4G LTE module as shown in the image The Base board size shall be 240 x 140 mm, RF board size is 40 x 50 mm and LTE board ...
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Ferrite rod antenna improvements

Most early solid state portable MW AM radios used a ferrite rod antenna. Some valve receivers like Phillips in the late 1950s used ferrite rods also. The early Germanium RF transistors were not too ...
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Antenova M20057 active antenna is not working

I have decided to use Antenova product which is M20057 (datasheet) as an active GPS antenna. I am using Quectel L96 GNSS module. There is an internal chip antenna on L96 module and I have tried the ...
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Increase in gain of CP micro-strip patch antenna [duplicate]

I have successfully designed my circularly polarized patch antenna shown below. I used the slot method. Which as a bandwidth of 23MHz and a resonance frequency of 915MHz. Though the bandwidth is small ...
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Why a close conductor does not propagate electromagnetic signal

Here is the following video that i saw (really great video): https://www.youtube.com/watch?v=ZaXm6wau-jc Nevertheless, I do not understand why a close conductor (first part of the video) can not ...
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How do ZOR antennas work?

In a Dialog application note (AN-B-027), I ran into this rather curious antenna for 2.4GHz operation: This is on two PCB layers connected with vias; the whole thing is shorted together at DC, but ...
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Axial ratio of a square microstrip antenna

I am currently designing by CP microstrip antenna using CST. The picture is shown below. However, when I view the axial ratio plot, also shown below it is way above 3dB at 90 degrees. the patch is 31,...
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67 views

Where to connect the ground pad of chip antenna?

I am using chip antenna with grounding pad and feeding pad. Here is the datasheet and there is an application specification. There is a recommended matching network, however I am using pi matching ...
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Smartwatch GSM antenna design

Which antenna design is the most applicable to a 2G smartwatch (about 40x40mm)? I have tried some sketchy ultra-short (about λ/8) whip antennas, but due to a fairly small ground plane and unfortunate ...
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Connecting a 75 ohm device to a 50 ohm antenna

I have a device operating at low-frequencies (470 - 790 MHz, Television White Space), which works with a 75 ohm antenna. I want to connect this to a 50 ohm antenna instead. The 75 ohm end has an F-...
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Microstrip square patch design [duplicate]

Circular polarized micro-strip patch antenna This question defers from the previous in that I want to know how to calculate the lengths for A,B and C. I want to know how to calculate the values of A,...
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63 views

Impedance matching between rectifier and antenna?

I have a confusion about the impedance matching between the antenna and the RF-DC rectifier. The antenna(915MHz) was bought from the market and the datasheet says its impedance is 50ohm. However, I ...
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Approrpiate Guage wire for 12v 1amp power supply?

I am looking to power a Wineguard 12v Antenna Amplifier off a pc power supply. However I am wondering what gauge wire is right. The run will be about 4 feet total (2 ft each direction) at 12v with a ...
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Experimental loss measurement of simple wireless link

I connect a simple SDR to a spectrum analyzer (SA) and measure the output power. The SDR outputs a single tone at 1 GHz; between SDR and SA is a lowpass filter: With gain setting GTX1 I measure -53....
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Can I cut a U.FL cable to make it shorter?

I want to fit a antenna in a small case. So I want to cut the U.FL cable to make it shorter but I was worried if I would decrease its sensitivity.
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Circular polarized micro-strip patch antenna

Circular/ Elliptical patch antenna design after a bit more research I realized what my mistake was, after a user pointed it out. As such my new post. I have come across a CIRCULAR POLARIZED PATCH ...
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What could potentially affect some specific LoRa frequencies among others and how to mitigate it?

I have started a small LoRaWAN network. I already have setup: 1x LoRaWAN gateway (LAIRD RG186, using EU863-870); 4x T/RH Nodes (Dragino LHT65, same standard); LoRa ...
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Circular/ Elliptical patch antenna design

I am trying to design a circularly/elliptical polarised antenna like the one in the picture. My frequency is 915MHz, a dielectric constant of 4.4, the thickness of the substrate is 1.6mm, thickness of ...
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Conceptual question about Frii's equation

That's a pretty basic one but for some reason I am stuck now: Suppose I have a transmitter that transmits Ptx=4W_EIRP with an ideal, omni-directional antenna. The power applied to the antenna ...