Design a RF Mixer.......????

[Rfboy]

microstripline balanced mixer design

Hi guys, I need some good ideas to design a rf mixer in the 10 - 12 -14 GHz frequency range with an If signal at 70 MHz.
I try to simulate a ring mixer in microstrip line whit ads 1.5 and mwoffice but not with good result.
If there are any body that knows any microstrip line mixer structure please help me!!!

Thank you

 

[nandopg]

step-by-step design a mixer

Hi friend:
The mixer using a ring directional coupler is a nice choice for UP converters, although you don't have a good OL rejection. Keep in mind however that one key point for a successful mixer design is to choose a suitable diode. Consult the HP web site. They have some charts to help you to choose a correct diode for your application. Also they have some AN that can help you to choose the best structure for your application.
No metter structure is going to be used, I follow a general approach to develop mixers in the 8 to 14GHz band that I describe bellow step by step.
1- Simulate each part of the mixer as a stand alone structure, creating "primitives".
2- Connect step by step the "primitives" ajusting their interconnection in order to keep the specs in all ports.
3- Choose the diodes you are going to use to made up the mixer.
4- Connect the diodes in the structure and simulate the driving point impedance at, LO and RF ports. Having these datas plote the impdance paths on a Smith chart and derive a matching network. These structures should be kept as simple as possible, once the return loss in OL and RF ports are determinants for a good mixer spec.
5- So a non linear (Harmonic Balance) simulation is done regarding the hole structure. In this step, should be applyed one tone to the OL port and another to the RF port.
6- Still in 5, the optimizer should be adjusted so that the goals should address minimum insertion loss between the RF to IF ports. The best IL does correspond to the best OL rejection and the best RL for each port.
I hope the above can help you somehow.

NandoPG

 

[Rfboy]

diode mwoffice

Thak you nandopg......

I try to start with a new simulation..

Bye

 

[odyseus]

how can i choose rf mixer

See message below:-

<font size=-1>[ This Message was edited by: odyseus on 2001-06-19 23:43 ]</font>

 

[Needbias]

All you say above is about single balanced mixer design in X Band,but as all know double balanced mixer has much advantages then single balanced mixer in many aspects.what is the pratical consideration of these mixer?balun or other?

 

[Kit-the-great]

You can try a FET-mixer (see MWO examples). Diodes in mixers not always useful.

 

[Mazi3]

mixer

use harmonics mixer. it is cheap and easy to design.
You can find it in article in Microwave Journal, January 2000, pages 22-40, author dr. Matjaz Vidmar.

reference design use this design in 20GHz project.

 

[lightsider]

Just moved this thread to a more appropriate section!
Pls do continue your discussion. :spoko: