Microwave High Pass Filter Phase Shifting

Hi, all

I have a problem here,,
How can i design a High Pass Filter with given phase shift??

Thank you

When the input frequency is above the filter's pole frequency, phase leads.

When it is below the pole frequency, phase lags.

To obtain a particular phase shift will involve drawing parallelogram shapes, with resistance being one axis, and reactance being the other axis.

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The phase shifts can be accentuated by using higher order filters.

As shown in graphs in the article below.

Phase Response in Active Filters -- Part 2, the Low-Pass and High-Pass Response

http://www.analog.com/library/analogDialogue/archives/43-09/active_filters.html

Thanks for the reply,,
but i still can't get with this picture

How can the phase response is like that, unlike the phase response at the article above???

the filter specification on the picture is :
the operation frequency is 5150 MHz - 5875 MHz
cut-off frequency is 1 GHz
Bandwidth is 800 MHz

monolothics said:

Hi, all
I have a problem here,,
How can i design a High Pass Filter with given phase shift??
Thank you

Click to expand...

Please reformulate your question. To me it is not clear what you really want to know.

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BradtheRad said:

When the input frequency is above the filter's pole frequency, phase leads.
When it is below the pole frequency, phase lags.

Click to expand...

Phase lags?

First order highpass: Phase goes from +90 to zero deg
Second order: Phase goes from +180 to zero deg.

LvW said:

Phase lags?

First order highpass: Phase goes from +90 to zero deg
Second order: Phase goes from +180 to zero deg.

Click to expand...

Thank you, you are correct. I should have listened to my inner critic saying I was reckless and my statement needed further defining.

A capacitor alone, or a coil alone, can only shift phase within a range of 90 degrees. (First order.)

I had spent time watching a second order filter (two capacitors, or coil and capacitor). I watched how it shifts a sinewave before and after the 90 degree mark. (A recent thread was asking about a filter that leads 90 degrees.)

I watched sinewaves going across the screen. I watched lissajous figures changing shape.

I developed tunnel vision from fixating on the 90 degree figure. It caused me to think of the phase shift as leading and lagging, whereas it was only phase leading, in the range you stated.

A third order filter goes yet a further step more.

Please reformulate your question. To me it is not clear what you really want to know.

Click to expand...

What i wanto to know is, how can i design a HPF or LPF with an output of certain phase shift???
for example, i want a HPF that can give a 22,5 degree phase shift, how can i do that??

monolothics said:

What i wanto to know is, how can i design a HPF or LPF with an output of certain phase shift???
for example, i want a HPF that can give a 22,5 degree phase shift, how can i do that??

Click to expand...

What means "certain phase shift"? A certain value at one single frequency or a certain phase function?

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BradtheRad said:

........ It caused me to think of the phase shift as leading and lagging, whereas it was only phase leading, in the range you stated.

Click to expand...

On the other hand - one could ask, however: What means "90 deg phase lead"? Isn`t it more correct to speak about "270 deg phase lag"? Perhaps a question of "cause and effect"?

LvW said:

What means "certain phase shift"? A certain value at one single frequency or a certain phase function?

Click to expand...

what i mean is a certain value of phase at one single frequency

The following link gives you some diagrams with a normalized frequency axis - and it shouldn`t be a problem for you to find the desired frequency and phase shift.
https://www.analog.com/library/analogDialogue/archives/41-10/phase_relations.html

Another option would be to use an allpass circuit with constant amplitude.