how can o design a wideband amp??

• Nov 20, 2003

• #1

W

wjnbry

Member level 2

Joined

Sep 9, 2003

Messages

48

Helped

1

Reputation

2

Reaction score

1

Trophy points

1,288

Activity points

460

wideband amp

Help me please?
i wan to design a 6GHz amp working from 5 to 7GHz.
i have never designed this sort of amp.
i am looking for these topics and some success designs.
thank you!

 

• Nov 20, 2003

• #2

E

Element_115

Advanced Member level 2

Joined

Mar 23, 2002

Messages

508

Helped

72

Reputation

144

Reaction score

43

Trophy points

1,308

Activity points

3,755

The common method is :
1) Find a FET that works to your Spec
(Note that Gain is the trade for Bandwidth!)

2) The input should go Lange Coupler w/the 2 output ports
going to a FET each (with the match networks of course)
The other port shuld be terminated with a Good 50 Ohm
load.

3) Then optimize the input and output networks to meet your
Spec.

4) recombined the FET's w/ another Lange Coupler.(Also treminated)


______
input--> | |---50Ohm
| |
50Ohm-| | --> Output
|______|


Hope this helps
Good Luck

 

• Nov 20, 2003

• #3

C

costox

Full Member level 4

Joined

Mar 5, 2002

Messages

196

Helped

5

Reputation

10

Reaction score

5

Trophy points

1,298

Activity points

1,539

This is NOT really wideband. When you say wideband, it's usually >10 GHz bandwidth. If you look at www.ieeexplore.ieee.org, wideband amp are usually a "distributed amplifier".

Now I notice that the other reply is not really helping because there are so many way to design your amp (7GHz, 2 GHz bandwidth).

So instead of giving you some trivial instructions which won't help you much, I'll tell you this: use @DS. There are many good example (and design guide) in it. And pick the book:
Designing microwave circuits by exact synthesis / Brian J. Minnis.

If this doesn't help you, I don't know what will !

 

• Nov 20, 2003

• #4

M

musasu

Newbie level 1

Joined

May 11, 2003

Messages

1

Helped

0

Reputation

0

Reaction score

0

Trophy points

1,281

Activity points

8

10 mhz to 500 mhz amp circuit and design theory...


URL **broken link removed**

bye

 

• Nov 20, 2003

• #5

BigBoss

Advanced Member level 6

Joined

Nov 17, 2001

Messages

5,948

Helped

1,609

Reputation

3,225

Reaction score

1,592

Trophy points

1,393

Location

Türkiye

Activity points

35,747

wjnbry said:

Help me please?
i wan to design a 6GHz amp working from 5 to 7GHz.
i have never designed this sort of amp.
i am looking for these topics and some success designs.
thank you!

Click to expand...

What kind of amplifier do you intend to design? Low Noise , High Gain , High Power ? Please be specific..

What is your flatness ? What are your reflections ? Cost ? Technology ? Reliability ? Productibility ? etc etc..

If you inform us more specific , we may help you..

 

• Nov 21, 2003

• #6

flyhigh

Advanced Member level 1

Joined

Nov 12, 2003

Messages

408

Helped

69

Reputation

138

Reaction score

31

Trophy points

1,308

Location

somewhere over the rainbow

Activity points

4,775

I agree this is not wideband requirement in nature, and also much more data is needed to give resonably close answer to particular situation. Maybe even some amps available on the market can be used in your case? If I remember correctly, one of Mini Circuit's ERA stil has some very good performances it this range as a general low-power device? Maybe someone can update this more precisely, I used them some time ago and had lost the information.

 

• Nov 21, 2003

• #7

Kit-the-great

Full Member level 3

Joined

Mar 30, 2002

Messages

150

Helped

5

Reputation

10

Reaction score

3

Trophy points

1,298

Location

Russia

Activity points

1,318

There is no problem to design 5-7GHz low power (up to 10 mW) amplifier. The really problem is to matching high power FET's (on 1W output for ex.) In this case You must design a very complex matching structure, because the:
1. Zin and Zout of high power FETs is low-Ohm
2. S12 too large, because the FET's gate too width.

Best regards,
Kit-the-great

 

• Nov 24, 2003

• #8

W

wjnbry

Member level 2

Joined

Sep 9, 2003

Messages

48

Helped

1

Reputation

2

Reaction score

1

Trophy points

1,288

Activity points

460

many thanks for all of up my good friends!
the amp's Pout is 24dbm,ripple<1dB.
i want to design it with 2 stages of fet(fhc057, FUJITSU) in MIC.
i've been worked in rf major for 2 yeas.
please give me some similar designs and examples.
best regards to you!

 

• Nov 24, 2003

• #9

H

HO_220

Member level 2

Joined

Dec 2, 2002

Messages

52

Helped

0

Reputation

0

Reaction score

0

Trophy points

1,286

Activity points

308

Hi.
you can use MMIC such as ERA-MAR and Gali amplifiers for these specs.
It is easy to use these.
Bests.

 

• Nov 24, 2003

• #10

A

AL0117

Full Member level 3

Joined

Jul 25, 2003

Messages

178

Helped

10

Reputation

20

Reaction score

3

Trophy points

1,298

Location

dracu-la-nd

Activity points

1,935

Hi wjnbry,

what would be Pout = 24 dBm, nominal power or P1dB?
The Era, Mar and Gali's has maximum output power rated to 18dBm (P1dB), so even if the freq range is suitable for you, they can't be used.

I don't find any kind of info about the fhc057, is still in production? What is the P1dB of it?

regards, Al

 

• Nov 25, 2003

• #11

W

wjnbry

Member level 2

Joined

Sep 9, 2003

Messages

48

Helped

1

Reputation

2

Reaction score

1

Trophy points

1,288

Activity points

460

FLC057WG
P1dB = 27.0dBm
High Gain: G1dB = 9.0dB(Typ.)
design goal:
Gain=17dB(2 stages)
Ripple<1dB(5~7GHz)
P1dB > 24dBm

FLC057WG
C-Band Power GaAs FET
S-PARAMETERS
VDS = 10V, IDS = 125mA
FREQUENCY S11 S21 S12 S22
(MHZ) MAG ANG MAG ANG MAG ANG MAG ANG
500 .973 -47.9 7.249 147.9 .016 60.6 .545 -20.4
1000 .941 -85.1 5.946 121.8 .026 38.1 .519 -38.2
2000 .912 -129.5 3.846 86.0 .033 8.9 .514 -66.2
3000 .897 -151.8 2.675 62.2 .033 -8.5 .562 -86.5
4000 .889 -164.8 2.058 44.1 .032 -17.6 .618 -101.2
5000 .881 -176.2 1.712 27.8 .033 -25.1 .658 -113.0
6000 .869 171.6 1.506 11.2 .033 -31.0 .689 -125.1
7000 .847 159.0 1.339 -6.1 .035 -39.4 .717 -138.5
8000 .816 148.5 1.199 -21.6 .033 -41.3 .745 -149.3
9000 .787 139.7 1.125 -35.4 .037 -41.0 .773 -157.4
10000 .740 129.4 1.149 -49.4 .045 -40.5 .796 -163.1


at 4 GHz,it's unstabality.

 

• Nov 25, 2003

• #12

BigBoss

Advanced Member level 6

Joined

Nov 17, 2001

Messages

5,948

Helped

1,609

Reputation

3,225

Reaction score

1,592

Trophy points

1,393

Location

Türkiye

Activity points

35,747

Without nonlinear model , it's not possible to find Pout of this transistor.
S-Parameters are only valid in small signal operating area.
Data's are not sufficient..

 

• Nov 25, 2003

• #13

A

AL0117

Full Member level 3

Joined

Jul 25, 2003

Messages

178

Helped

10

Reputation

20

Reaction score

3

Trophy points

1,298

Location

dracu-la-nd

Activity points

1,935

I recommand the following lecture:
"MESFET Power Amplifier Design:Small Signal Approach" (How to design a Power Amplifier without a large signal device model?)

you can d/l it from :

hxxp://eesof.tm.@gilent.com/pdf/amp_ss.pdf

(x=t, @=a)

regards, Al

 

• Dec 30, 2004

• #14

C

costox

Full Member level 4

Joined

Mar 5, 2002

Messages

196

Helped

5

Reputation

10

Reaction score

5

Trophy points

1,298

Activity points

1,539

Just for those who read all the way down here...
For TRULY WIDEBAND, (or Ultra-wideband), and I'm talking about 20GHz or even 40 GHz bandwidth, search for "Distributed Amplifiers".

Thanks.

 

• Dec 30, 2004

• #15

abdoeng

Advanced Member level 2

Joined

Feb 22, 2004

Messages

647

Helped

76

Reputation

152

Reaction score

63

Trophy points

1,308

Activity points

3,810

wjnbry said:

Help me please?
i wan to design a 6GHz amp working from 5 to 7GHz.
i have never designed this sort of amp.
i am looking for these topics and some success designs.
thank you!

Click to expand...

hi,i try to simulate amp of fet atf36077 with band 8:12 ghz,u can use it in band 5 to 7 ,it is stable,but for wide band u must use multible match using stub,i can upload u with one of my trial design
regards