Final Year Project: Dual-Frequency Microstrip Patch Antenna

[nkphnx]

Dear all, anyone of you antenna gurus here could shed some light on how to design a dual frequency microstrip patch antenna? The frequency range is above 10GHz, preferably 10GHz and 12GHz. Does this design involve any mathematical analysis? and are there any softwares that I can use for design? I'm using FR4 substrate btw... Thanx a lot

 

[kleinesmurf69]

Re: Final Year Project: Dual-Frequency Microstrip Patch Ante

hello

using fr4 at these frequencies is not a good idea, the substrate is way too lossy. the result will be an antenna with very low efficiency, the bandwidth will increase though . It is better to use ro4003 or another microwave substrate. Could you give some more design specs like polarization, bandwidth...

best regards

 

[nkphnx]

Re: Final Year Project: Dual-Frequency Microstrip Patch Ante

Hi there! Either linear or circular would be just fine and for the bandwidth, I was thinking something like around 200MHz for each frequency...Don't know if this is of much help though, I suck at microstrips but thanx a lot! and one more thing, is there any mathematical approaches used in designing dual frequency microstrip antennas like these or are they purely trial & error/experimental? :?

 

[kleinesmurf69]

Re: Final Year Project: Dual-Frequency Microstrip Patch Ante

hello

it's a lot easier to design small band antennas than broadband antennas. 200 MHz at 10 GHz would be 2 % bandwidth, that's small band. dual band structures are usually built by exciting 2 modes. the natural modes are usually at f0, 2*f0... but the higher mode can be shifted by using slots and/or shorts. the frequency ratio 10 GHz vs. 12 GHz is only 1.2. that's pretty close to 1. a single broadband structure may be easier, but without the FR4 then. there are a lot of dual band structures available in the literature.

best regards

 

[nkphnx]

Re: Final Year Project: Dual-Frequency Microstrip Patch Ante

Icic.. any recommended literature on this though? cos there are not many variations on microstrip references here in my library and most of the time I need to search elsewhere I was fiddling around with ADS the other day and experimented with some weird antenna designs and a few of them gave pretty good S11 response but the problem with some of them are their simulated radiation patterns.. There's a particular one shaped like a nazi logo with an off-center feed point which produces a nice 10GHz and 12GHz response but the radiation pattern at 10GHz has a little weird dimple on the side of the hemisphere...I was wondering if this could be remedied? the radiation at 12GHz looks fine though... Regards :wink:

 

[kleinesmurf69]

Re: Final Year Project: Dual-Frequency Microstrip Patch Ante

any decent book about microstrip antennas should give a few examples
more specific books are:
broadband microstrip antennas, Girish Kumar et al., artech house
Compact and Broadband Microstrip Antennas, Kin-lu Wong, Wiley

best regards

 

[nkphnx]

Thanx kleine, i'll try out the books you've mentioned... regards