Extremely narrow beam antenna

I am looking for extremely narrow beam microstrip antenna. Is it possible? I dont have any other criterion like return loss or operating frequency. All suggestions are welcome. Suggestion for antennas having pencil beam radiation are also welcome although it may not suffice in my case.

Hi!
You could try an array of half-wave dipoles at λ/2. All dipoles need to be driven with the same power.
For many dipoles, a very tight beam is projected at right angles to the array. The more dipoles used, the tighter the beam in terms of sidelobes, although the beam is wider.

Narrow beam == High Gain

You can try to design a microstrip patch array.

A simple microstrip Yagi can have a narrower beam-width than a complicated dipole array antenna.

Thanks 2 all for their suggestions... i m looking for some more ideas.....something with antenna beam width of less than 2° at gain of say 4dbi. Narrow bandwidth of the antenna is also acceptable

It violates basic physics.

A beamwidth of 2 degs is around a peak gain of 30+ dBi.

check the attached file

Are you referring to page 3?

Figure 3 is normalise to 0dB. Furthermore, in the paragraph, the author stated the measured gain is 50dBic.

I second that. A rough estimate of the gain (or directivity) quoted from Balanis is:
10*log(32400/theta_1/theta_2)
where theta_1 and theta_2 are the -3dB angles in the E & H planes.
If both planes have 2 degs, it means 39dBi of gain (typically it will be less). So it will lie somewhere in the 30+ dBi as kgec mentioned.