what are the new frequencies that people are trying to use?

switched resonator vco

Hi all,

I need some favor from you experienced guys. What are the frequencies
that people are trying to use? I mean, the frequencies or bands that are
still developing. I am doing some research about dual-band (even tri-
band) RF VCO and frequency synthesizer and I am just trying to find
some potential topics for thesis or project.

Super thanks.

There is substantial interest in the 60 GHz band for broadband digital links to solve the first/last mile problem. In the US, the FCC has opened up some spectrum at 60 GHz for unlicensed radio. There is a working group also looking at w-band around 90 GHz
for the same type applications.

have you heard all the hype about bluetooth? that uses the next lowest "free-for-all" band and can pack huge amounts of data thru a low-power rf link. supposed to take over cabling - rf keyboard, rf mouse, rf toilet, etc. personally i hate that much rf adsorbing into my brain but bluetooth amplifiers, bluetooth VCO's, bluetooth anything RF cmos are really pulling in the dough. your thesis would obvioulsy be dated 200x when people read it in 2050, but right now it's an easy field to get huge acceptance in.

Re: what are the new frequencies that people are trying to u

Thanks a lot, mmwave and electronrancher!

BTW, can you guys tell me about the specs or where I can get that
kinda information? I heared that next wireless network is about
8GHz or something like that, is that true?

We are using CMOS/SiGe now so I think 60GHz is kinda way from
those processes. I am not saying that mmwave's suggestion is
useless for me. I really appreciate any suggestions. I took many
microwave courses and I really like it. But you know, advisor is the
one who pays you.

More suggestions are welcomed. Super super thanks.

wide range radio

Most modern radio receivers use high side mixing and have the IF at 1.5 or more times the highest RF frequency.

For your thesis you could do a first LO for a receiver that tunes DC to 2500 MHz. You could have an IF of 3500 MHz which will make the vco tune from 2500 to 6000 MHz.

This could be sold to companies like ICOM, Kenwood, and Yaesu that make hobby receivers. If the phase noise specification and tuning step was good enough it could be used in military and commercial grade receivers.

In military receivers that are battery powered portable, power drain is very important.

Re: what are the new frequencies that people are trying to u

As I see your problem, you have two options. One is to make wideband VCO that spans more than octave like Flatulent wrote. Other option is to try to make some kind of low cost VCO with switched resonator and tuning elements so you can span few of actual ISM bands (433, 866, 2400 and 5600 MHz). The potential for such devices is quite large since 802.11 standard uses upper two bands and lower two are extensivelu used for short range applications. There is very nice article from S. Alechno about switched resonator VCO at the Eagleware web page, maybe you find it usefull:

**broken link removed**

Good luck
D

Re: what are the new frequencies that people are trying to u

Thanks for all the replies. After discuss with my advisor, I got some options. One is to improve something that already done, like design a tri-band VCO for GSM/Bluetooth with extremely low power. Second one is to design a distributed VCO above 10GHz. Last one is to design a ultra wide band VCO (quote: 2GHz to 20GHz). I have been told that I should use CMOS or SiGe technology for all of those choices.

Actually, I already got a 3GHz VCO with 26% tuning range by using TSMC 0.35um. I think change the structure of varactor should be able to boost the tuning range. I read some papers about the three-terminals varactor and they said that varactor can achieve very wide tuning range, eg. 100%. So I think flatulent's suggestion seems the easiest way for me to do it. However, my advisor don't want that kind of VCO. He wants 1. dual band or tri-band, 2. very high frequency (by using CMOS), 3. ultra wide band.

Any suggestion, again?

Re: what are the new frequencies that people are trying to u

1.See the following links for works done:

http://www.its.caltech.edu/~hajimiri/publications.html
**broken link removed**
**broken link removed**

2.for 60 ghz application see:
http://bwrc.eecs.berkeley.edu/Research/RF/ogre_project/
they want to design fully cmos transiver @ 60GHz!

3.for increasing tuning range of osc. the best way is switched tank, otherwize noise(substrate or device noise) will amplified by vco gain in pll loop and a low quality signal will be abtained!

4. another intersting area in rf design is UWB(ultra wide band), it has several benefit in respect to other modulation/communication methods like lower multi path efect in short range wireless communication specially home used.

normally it is better to choose the application first and then looking for its building blocks; but in very high frequency all of the system like modulation method, power amplifier, mixer local osc....must be considered for design and these will complicate design process.

BEST!

but
what can me do in the new frequency??
is there any good book for this so high frequency

qiang said:

but
what can me do in the new frequency??
is there any good book for this so high frequency

Click to expand...

implementation of several subblock and evan systems has been reportsd in lower 10 GHz in IEEE and some of them can be finded in the universities home pages like stanford, UCLS, Berkeley, caltech...

for very high frequency like 60 GHz u must wait for several years until researches reports becomes available and u can not find any book in this area since there is no former experiment!

commercial products like RFICs are experienced in universities firstly and after successful results they are introduced by large companies and at the same time u can see some books in this specific field, so it is causal to follow the university activities and papers to wait for books!

BEST!

Re: what are the new frequencies that people are trying to u

Hi, I got some questions for you guys again .
Is anyone know the specification of the UWB? All I know is that it's about 3 to 10GHz, and the bandwidth is around 500MHz. How about the other specifications such as phase noise?

Re: what are the new frequencies that people are trying to u

u can find alot of useful infos here:
https://developer.intel.com/technology/ultrawideband/
as u see intel's R&D branch is working in this field!

BEST!