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Type: Posts; User: vfone

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1. ## Thread: Ingress in coaxial at FM frequency

by vfone
Replies
2
Views
144

### [SOLVED]Closed: Re: Ingress in coaxial at FM frequency

I think your definition "ingress effect" can be given by the "shielding effectiveness" which is a characteristic mentioned in most of the (good) coax cables data sheets.
For example the double...
2. ## Thread: NFC System with antenna which can provide from 1 A/m to 7.5 A/m signal strength

by vfone
Replies
3
Views
221

### [SOLVED]Closed: Re: NFC System with antenna which can provide from 1 A/m to 7.5 A/m signal strength

The transmitter output power of the S4100 module is 200mW. To get more signal strength you need to use an external power amplifier. I assume couple of watts (maybe less) will provide your desired...

by vfone
Replies
1
Views
175

### Closed: Re: 2.4Ghz Rectifier design by ADS

Before taking a decision about impedance matching you have to think adding an amount of DC bias to the diodes, which will improve the rectifier efficiency.
After you applied the DC bias (forward...
4. ## Thread: Understanding of noise figure

by vfone
Replies
2
Views
260

### Closed: Re: Understanding of noise figure

F(total) = F1 + (F2 – 1)/G1
where:
F(total) = Total noise factor
F = Noise factor of each stage
Noise Figure (dB) = 10*LOG(F)
G = Gain of each stage (linear not in dB)

From the two stage...
5. ## Thread: How to find cutoff frequency of the circuits

by vfone
Replies
3
Views
303

### Closed: Re: How to find cutoff frequency of the circuits

I don't think you can get a simple equation for finding the 3dB bandwidth for such multi element circuits.
But there are many freeware circuit simulators that can do this job:
...
6. ## Thread: Dual feed patch antenna with single connector

by vfone
Replies
2
Views
251

### Closed: Re: Dual feed patch antenna with single connector

156093

Found at:
https://d3i71xaburhd42.cloudfront.net/c8a59b3ca833b98068071517aea556552eb1de41/2-Figure3-1.png
7. ## Thread: Ways to analyze the harmonic distortions after mixing

by vfone
Replies
1
Views
165

### [SOLVED]Closed: Re: Ways to analyze the harmonic distortions after mixing

Here you can find few methods how to test the IP3 (and in-band distortions) of a mixer.

https://www.markimicrowave.com/blog/how-to-measure-mixer-ip3-and-identify-potential-error-sources/
8. ## Thread: Microstrip line and ground on same layer

by vfone
Replies
14
Views
777

### Closed: Re: Microstrip line and ground on same layer

There is no reason to design a high-impedance microstrip line with nearby ground on the same layer, because any nearby ground will decrease the impedance of the line, and you will not have anymore a...
9. ## Thread: Microstrip line and ground on same layer

by vfone
Replies
14
Views
777

### Closed: Re: Microstrip line and ground on same layer

The rule of thumb that you ask for is that the ground plane on the same layer should be at a distance greater than 1.5 x width_of_the_line.
For example if the width of the microstrip line is 1mm the...

by vfone
Replies
3
Views
350

### Closed: Re: Question about PC3.5mm and SMA connectors

3.5mm and SMA may be mechanically compatible, but for very precise measurements, connecting them results a small but measurable discontinuity.
A damaged or out of spec SMA connector can damage a...
11. ## Thread: Captured field by Array Antenna

by vfone
Replies
16
Views
746

### Closed: Re: Captured field by Array Antenna

Seems that you know ALL the answers...before placing the questions here...
12. ## Thread: Captured field by Array Antenna

by vfone
Replies
16
Views
746

### Closed: Re: Captured field by Array Antenna

The total field of an antenna array is determined by the vector summation of the induction fields radiated by the individual antenna elements.
This assumes that the current in each element is the...

by vfone
Replies
3
Views
275

### Closed: Re: How does intermodulation affect receiver system?

Yes, you can say in this way...

by vfone
Replies
3
Views
275

### Closed: Re: How does intermodulation affect receiver system?

Indeed...

The main concern of intermodulation is reducing the receiver sensitivity.

To understand how intermodulation level is measured:
- the receiver is tuned on one of the frequencies of...
15. ## Thread: Can you help me get S-parameter file of Mitsubishi MGF4937AM and Infineon CFY67

by vfone
Replies
6
Views
437

### Closed: Re: Can you help me get S-parameter file of Mitsubishi MGF4937AM and Infineon CFY67

Unfortunately, today most of the universities do not bother teaching students how to measure s-parameters of a transistor.
16. ## Thread: Relay selection for Ultrasonic signals

by vfone
Replies
5
Views
405

### Closed: Re: Relay selection for Ultrasonic signals

And also, because ARJ2024 is a microwave relay the isolation is given only in dB.
30dB isolation doesn't tell you anything about high-voltage isolation capabilities.
As was mentioned, any of the...
17. ## Thread: Relay selection for Ultrasonic signals

by vfone
Replies
5
Views
405

### Closed: Re: Relay selection for Ultrasonic signals

If you do not switch a 900V signal, most of the small signal relays available on the market support at least 1000V between contacts (isolation) and can handle a 25MHz signal.
But if want to switch a...
18. ## Thread: Why are all reference sensitivity requirement of all bands different in WCDMA (UMTS)

by vfone
Replies
2
Views
300

### [SOLVED]Closed: Re: Why are all reference sensitivity requirement of all bands different in WCDMA (UM

The basic noise power density (kTB) of a WCDMA receiver is -108 dBm/3.84 MHz, at 290K (17°C).

The 3GPP spec set various reference sensitivities in different bands function of potential interferers...
19. ## Thread: Pulse distortion after amplification

by vfone
Replies
4
Views
364

### Closed: Re: Pulse distortion after amplification

By definition an LNA should NOT be saturated in any cases.
Reduce the input level into LNA, or use a higher IP3 device (with higher P1dB) which can handle higher input levels.
20. ## Thread: Why is there always a shunt inductor for SMD (Surface Mount Device) antenna?

by vfone
Replies
8
Views
586

### [SOLVED]Closed: Re: Why is there always a shunt inductor for SMD (Surface Mount Device) antenna?

Yes, series inductor is more convenient, but the matching can be done with almost any configuration.
These chip antennas have awful internal impedance which require unusual matching typologies.
21. ## Thread: Why is there always a shunt inductor for SMD (Surface Mount Device) antenna?

by vfone
Replies
8
Views
586

### [SOLVED]Closed: Re: Why is there always a shunt inductor for SMD (Surface Mount Device) antenna?

This come from the theory. Small (or short) antennas are capacitive.
So, for impedance matching they need an inductor (or more inductors) to "tune out" this capacitance.
22. ## Thread: Can you help me get S-parameter file of HJFET transistor

by vfone
Replies
2
Views
414

### Closed: Re: Can you help me get S-parameter file of HJFET transistor

Here it is...
23. ## Thread: 1dB compression point and jamming signals

by vfone
Replies
3
Views
408

### Closed: Re: 1dB compression point and jamming signals

P1dB of the LNA should be higher as possible, but keeping in the same time the LNA noise figure (and the cost) low.
In an RF system, band filters could help the LNA to have lower P1dB, if the...
24. ## Thread: Antenna pcb in commercial key fob

by vfone
Replies
8
Views
578

### Closed: Re: Antenna pcb in commercial key fob

https://infocenter.nordicsemi.com/pdf/nwp_008.pdf
25. ## Thread: Recommendation needed for gain of antenna for a 2.4 GHz wifi extender

by vfone
Replies
9
Views
733

### Closed: Re: Recommendation needed for gain of antenna for a 2.4 GHz wifi extender

RG58 and RG174 are very bad coax cables to use at 2.4GHz.
Cheap RG316 from any Chinese vendor is better:
...
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