doubt in designing coaxialfeed in HFSS

I have designd an MIMO antenna with Co-axial feed .whether co-axial feed should be within the airbox or out of airbox .Here i have given equal height for airbox and feed.My design should generate frequency range for GSM, PCS and LTE .BY i am getting dip only aound 3 to 4 GHZ,that to around -2.25 db.my center frequency is 2.5 GHz.what changes can i make to bring the return loss below -10 db.i have attached my design.

The excitation port should be inside the airbox if you are using a lumped port; if you are using a waveport, it should be on the edge of the airbox. It should never be outside the airbox.

Thakyou sir .i am designing a cavity backed bowtie antenna .i am using lumped port.whether the feed should be within the cavity box or out of cavity box.or at the edge .

hi, you mean both wave port and air box can overlap (i.e they can share the same plane)?

Whichever is most realistic in your case.




Yes, that is correct.

[QUOTE=PlanarMetamaterials;1537945]Whichever is most realistic in your case.



i have a small doubt reg cpw feed, can u clarify in which direction the integration line should be taken in the case of cpw feed(standard), i believe it should be directed from central conductor strip to the one of the side conductors am i right ?

That should be correct.

sorry i am using waveport.if my feed is outside the airbox .The intersection problem occurs .how to solve it