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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73 views

Definition of antenna efficiency

I have two definitions for antenna efficiency: \$ \varepsilon = \dfrac{P_{rad}}{P_{in}}\$ and \$ \varepsilon = \dfrac{R_{rad}}{R_{rad} + R_{ohm}}\$ Coming from physics, I was wondering if there is ...
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0answers
27 views

RFID antennae at distances of 2 cm

I want to arrange RFID antennae spaced equally at distances of 2 cm. And I'll be connecting those using a MUX. The other end of the MUX is connected to a reader. How should I go about designing that? ...
1
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1answer
86 views

Wi-Fi transmitter/receiver in close proximity: Override interference?

I'd like to control a camera via Wi-Fi (zoom, trigger shutter, etc.), and possibly also capture a live video stream. This will be at an event with a huge number of Wi-Fi devices, and connectivity is ...
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0answers
64 views

Using a flagpole for a Wifi antenna

I would love to use an existing flagpole as a makeshift Wifi antenna, but am not allowed to attach anything to it. I.e. no J-pole, mounted antenna or coax running down it. Will this be at all remotely ...
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0answers
22 views

PCB antenna: ground plane layers and dimensions?

I'm using an Inverted-F antenna on a Bluetooth Low Energy peripheral/device I'm designing and I'm not sure how I should design the ground plane. The ground plane should not be "too big" nor "too ...
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0answers
23 views

antenna matching with lumped elements

Is there any resources online that describe how to match antenna elements to a TX line with a lumped element matching network? I've got a 50 ohm load and a TX line that i'm trying to match to a ...
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1answer
33 views

Using 1/4 dipole antenna on RF module

Good day to you all. Am new to RF designs. Presently, am working on a device using RF module for transmitting my signal from TX to RX. Am using the common 315-433MHZ RF module bought from ebay. My ...
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0answers
29 views

Wifi Antenna Selection

For a project I like to use a Wifi Antenna that has directional properties. Imagine the little box as my product that sits on the ground and I want most of the energy to be transmitted upwards. ...
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0answers
36 views

Can Wi-Fi Antennas be Curved?

I'm designing a small device that needs to talk WiFi and it needs to have a powerful antenna. I'm looking at using the Intel Edison for the processor, it has two flavors - one with a built-in antenna ...
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1answer
63 views

What is the name of the tiny PCB radio connectors? (e.g. Apple WiFi/Bluetooth antenna ports)

What is the name of the nearly-flush flat antenna connector often found in laptops/tablets for its external antennas? They are very small and the antenna lead usually has a 90º male plug that snaps ...
2
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1answer
269 views

2.4GHz antenna feed routed through pcb via?

I'm working on designing a BLE device, and have settled on using a chip antenna. It seems, however, that my BLE SoC is going to have to be on the underside of the board, which might be significantly ...
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1answer
56 views

what is meaning of wavelength in very short conductor length

I know the wavelength is distance between 2 point of maximum sine wave. when the conductor length is very shorter than wavelength, what is meaning of wavelength? ??(how long distance propagate in ...
3
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1answer
136 views

What is this type of radio fm antenna connector called?

I'm looking for an antenna replacement for my dad's busted radio (iHome IH8) and I'm having some trouble finding the name of this type of plug. The only things I find when searching online are coaxial ...
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4answers
3k views

True GPS Location - At the Antenna or Receiver Chip?

Suppose I have a GPS unit attached to an antenna through a 50 meter coax cable. How would the location as calculated by the GPS unit be affected by the cable length? As a bonus question, how would ...
0
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0answers
34 views

Why does this smart card use antenna with different space between turns along different sides?

I've extracted and zoomed to 400 percent parts of image from this post. The original image features the inner parts of Visa PayWave enabled smart card. Here're card corners zoomed to 400 percent so ...
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1answer
37 views

ANT-MMCX and Microstripe line and UHF RFID module circuit designing

Below, you see the only schematic of a 6 pages-datasheet of an UHF RFID module (working frequency = 840...930 MHz): There are three questions: What is that ANT-MMCX? I search it in Google and I ...
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0answers
48 views

Occasionally blinky reception; Damaged cable (pic incl.) contributing?

Please see: & Higher resolution versions are at (respectively) http://i.imgur.com/93Fk7HN & http://i.imgur.com/K7vTK52 Every few minutes our TV has pieces of the picture appear ...
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1answer
43 views

Wireless amplifier antenna

There is something like an antenna that works like an amplifier, repeating every signal in the device frequency operation range but wireless. I mean that this "dumb" active antenna receive every ...
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3answers
66 views

Can a magnetic wire be used to extend/strengthen the signal coverage of a cellphone? [closed]

When i'm inside of our apartment, getting a cellphone signal is very hard, often times I wouldn't get any bar in my iPhone. My unit is in the ground floor and is surrounded by tall walls. My apartment ...
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1answer
41 views

Send action signal via radio using energy generated by piezo

I have an idea going on in my mind but I am not sure if it is even feasible, so please be patient! Here is my problem. I have a set of chairs, say several dozens. I would like to be able to monitor ...
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1answer
44 views

Two 2.4GHz radio modules (XBee+Bluetooth) on same PCB. How to minimize interference?

I'm designing a PCB with XBee radio module and a bluetooth module (RFDuino SMD with XBee 2mW Radio). Since both of these modules are using 2.4GHz, are there any special consideration about how to ...
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1answer
114 views

how electron flow in circuite, when wavelenght is very long such as 5 kilometer?

1-My first question is: when signal with low frequency such as 100khz the wavelength of that is 5 kikometer that means between high and low voltage must be 5 kilometer .so when signal propagate by ...
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1answer
58 views

Can I create paths to two external GPS antennae but use only one

I am making a PCB for a SIM968 GSM/GPS device. Printing PCBs in my country is expensive. I am making this PCB for two different purposes. One is to work in an open environment where there is enough ...
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1answer
66 views

one antenna working as receiver and transmitter

I want to know, if an antenna which transmits and receives the reflected signal can be modeled as an impedance. For example, the antenna is coupled to a Collpits oscillator and sends out an ...
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1answer
39 views

Solder wire antenna on XBee Pro u.fl

I'd like to buy one XBee Pro with Wire Antenna, and another with an u.fl connector. The problem is that, on the only website I can buy them, the U.Fl one costs 20 € less than the one with a Wire ...
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1answer
73 views

Objections to use an RCA connector for antenna in broadcast FM receiver

Due to budget & space restrictions, I am thinking about replacing a PCB BNC connector used to attach an external FM antenna. It seems to me an RCA connector could be an option, given its good ...
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3answers
144 views

Possibility of an extremely directional antenna

I'm fairly new to RF technology, but a direction-finding application has come up where a highly directional antenna can offer a convenient solution, so I started searching for such antennas. Most, ...
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1answer
57 views

Antenna Gain explanation

I'm looking for an explanation about what type of relation have antenna gain with it's efficiency. For example I want to use a ceramic antenna that is a dipole antenna. It has: Average Gain of -0.5 ...
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0answers
40 views

HF RFID Impedance Matching

I come from a software background and I am learning about hardware. I built a simple arduino based bread board circuit that interfaces with a Skyetek M1-mini HF RFID module. I have had success using ...
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0answers
25 views

How antenna array factor is related to FFT of antenna weights

I have an uniform antenna array of N elements with unknown element spacing. Each element is fed with phase weights p1,p2,... ,pN. All elements are fed with uniform amplitude. I will take the M point ...
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0answers
57 views

Antenna elements within antenna arrays, confusion!

My questions here are regarding antenna array, RF chains, antenna elements, antenna gain. I will provide an example to illustrate question. Assuming we have 4 RF chains (transceivers) and a uniform ...
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1answer
66 views

Help to understand/ explore small sized 3G and GPS Antenna Design

I recently came across an exciting device called Automile, from Sweden and what caught my eye is this - I am really impressed by the packaging and overall quality of hardware integration they have ...
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1answer
41 views

Ceramic antenna for wifi applications

I want to ask how to choose correct ceramic antenna for wifi applications. I've very tight space constrictions and I need to use a small smd antenna. Which is the best antenna(characteristics) for ...
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1answer
51 views

How much power does a phone consume each time it ping its SIM's ID to the nearest cell tower? [closed]

I am trying to build a device than can be tracked through the cellular network. Like a phone, for every few second the device will ping its identity to near by cell tower, which will inform the Mobile ...
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0answers
44 views

What's the purpose of these peninsula-like areas in this smart card circuit?

Here's a scan of a stripped MIFARE Ultralight smart card. Note the underlined peninsula-like areas. They are simply connected from one end to the antenna track. They don't look like a patch antenna ...
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2answers
70 views

Why is outer turn of this smart card antenna wider than the other turns?

Here's a scan of a stripped MIFARE Ultralight smart card. Most of the wiring is the antenna which effectively consists of a single spiral track. The outer spiral turn clearly is a bit wider than the ...
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3answers
46 views

Dipole antenna VS. coil for RF transmission or recieving

Correct me if I am wrong, but all RF light waves are created via a changing electric and magnetic field. But when looking at all kinds of radios and RF circuits, this light wave is always made with a ...
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2answers
38 views

Adding U.FL connector to XBee

I recently bought two XBee Series 2 Pros, and I want to increase the range on them. I found an appropriate 2.4GHz antenna with a U.FL connector. I already have one XBee with a U.FL connector and from ...
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1answer
87 views

Basic NFC Loop Design on PCB

I'm a college student learning the basics of NFC loop antenna design. As a starting point, I'm trying to design a PCB-based rectangular NFC loop operating at 13.56 MHz, matched to 50Ω. (NFC ...
0
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1answer
171 views

Unknown short-circuit between GND and ANTENNA pins of GSM module

I have a Quectel M72FA GSM module, brand new one. I have just soldered it onto my PCB and found that: there is a short-circuit between the GND and RF_ANT pins. This is the pinout: I have checked ...
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2answers
97 views

configuring a DPDT switch to choose between two RF signals

I have 2 different signals coming in I wanted to be able to switch between them (choose what to transmit) using a simple DPDT switch. I have the following configuration, but I feel like I'm missing ...
0
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0answers
45 views

What does KFD stand for in a N type RF Connector

A RFID antenna supplier specified the antenna connector as N-50KFD Female. After a lot of googling I was unable to determine what does the KFD stand for. Is there a standard for these letters. I ...
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1answer
33 views

How do you account for receiver sensitivity in tranceiver half wave dipoles?

if you are to design 2 halfwave dipoles, both can transmit to each other using 3 watts and have receiver sensitivity of -80dbm (a picowatt). Suppose they are 800m and have same height from ground. How ...
0
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0answers
36 views

ANTENNA pin and GND pin low Ohmic resistance (looks like short-circuit) WISMO218 GPRS chip

I have for my school project a WISMO218 GPRS chip that I had to interface in order to send and receive SMSes, I had my board printed, soldered this chip (SMD) to the board and it seemed that the ...
2
votes
1answer
70 views

FM Antenna Question

I am a swim coach trying to play music for my swimmers while they swim. I am currently using this transmitter with this antenna . I have no issues with the transmitter as it is more than powerful ...
3
votes
3answers
366 views

What makes this active antenna “active?”

I'm using a external taoglas GPS/Glonass active antenna. It has a male SMA connector and I don't see where any voltage source hooks up to thing. So how is it active? Or does the power required for the ...
1
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1answer
51 views

Coplanar waveguide vs open space?

I'm routing a U.FL connector to a cellular module (Telit GE864). According to this calculator a 1mm track with 0.16mm gaps should provide a 52Ω impedance path to an U.FL antenna connector. A ...
1
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1answer
72 views

Interfacing a GPRS chip (WISMO218) with an RF antenna. Calculating line width for the right impedance

I want to interface the WISMO218 GPRS chip with an antenna. The antenna lines on the PCB board have to be very specific, otherwise the system won't work. I have uploaded the part of the datasheet that ...
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2answers
141 views

433mhz micro directional antenna design

I'm trying to build a Radio wave penetration device that register the RSSI on the RX module. There are two 433 transceivers one is the RX and the other TX - I want to place between them different ...
1
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2answers
184 views

Explanation for: A monopole antenna must contain a resistor (or equivalent) and therefore must have 2 terminals?

Could someone explain why this sentence makes sense: A monopole antenna transfers energy from electrical domain to the electromagnetic domain, hence must contain (equivalently) a resistor, hence ...