How to terminate microstrip line with 50 Ohm resistor to ground if there is 3v DC?

[Terminator3]

I want to terminate drain stub with 50 Ohm to ground. Do not want to use capacitor or microstrip DC-block before that. Problem with capacitor or DC block is that it can reflect unwanted frequency back to transistor. But it seems that it is not good idea with 3v and 50 Ohms there would be 60mA flowing and need to use big resistor like 1206, and waste of energy. I read about microstrip spiral can be used with foam absorber glued to it, the only alternative i thought about.

 

[BigBoss]

Problem with capacitor or DC block is that it can reflect unwanted frequency back to transistor.

Why ?? You're working at very high frequency ?? mmWave ??

 

[volker@muehlhaus]

Can you show a picture of the layout, and describe what you want to block where?

 

[vfone]

First of all, a component may reflect power, but not a frequency.

Second, there are DC blocks that works well at mmWaves, as the one in the example below.

https://www.jpier.org/PIERC/pierc30/04.12041618.pdf

 

[Terminator3]

Idea is to make parallel feedback oscillator with microstrips of arbitrary lenghths. Each microstrip terminated with 50 ohm to GND. Then it is possible to tune DR dielectric resonator position, many types, if sizes give reasonable coupling. And provide potentiometers for biasing. This is single test board for investigating DR phasing lines. Corrrect me if i am wrong.

 

[volker@muehlhaus]

I think a capacitor for DC-blocking is your best choice then. If will work (low enough impedance) over a reasonable frequency range, so that your C in series with the R presents a good ~ 50 Ohm load.

 

[D.A.(Tony)Stewart]

This technology has been around for many decades but grew rapidly for mobile use since early 90's

XO ( using quartz wafer or microslice quartz )
MEMS ( using Micro-Electro-Mechanical-System)
CO ( using high Q LC CMOS osc)
LCO ( not using CMOS)
DLO ( using delay lines or SAW filters or DR's with group delay)

First define impedance tolerance, or s-parms over frequency range including harmonics.
Then define signal swing and bias point.
Then define parameters of termination or transformer impedance of components. ( incl ESR & ESL or s-parms)
Define power consumption limits and temperature range.

Then choice becomes obvious.
This may include harmonic tune and/or block and temperature compensation.