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Could a micro-transmittting device, smaller than, say, a golf ball be employed to emit an ultra-narrow detectable beam, (e.g. 1mm) with range of one or 1.5 decimeter to 2 or less centimeter? The device must also include a microwave-rechargeable battery...

ElectroMag or Sonar?

The signal detector must fit inside the size of 2-3 pencil diameters... (no extreme battery parameter)

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Hi Jk. Welcome to Physics.SE. If this question is too much involved in EE, you could ask it over there :-) – Ϛѓăʑɏ βµԂԃϔ Jan 1 at 14:53
Your question is really unclear at the moment, could you edit and clarify it? – Manishearth♦ Jan 1 at 16:55

closed as not a real question by Ϛѓăʑɏ βµԂԃϔ, Manishearth♦ Jan 1 at 16:55

It's difficult to tell what is being asked here. This question is ambiguous, vague, incomplete, overly broad, or rhetorical and cannot be reasonably answered in its current form. For help clarifying this question so that it can be reopened, see the FAQ.

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I cannot be sure about engineering, but what you describe seems feasible from the point of view of physics. There may be several possibilities: ultrasound (say, above 10 MHz, otherwise you cannot get a narrow beam due to diffraction constraints), ultraviolet radiation, or a source of alpha radiation. It should be possible to choose the parameters in such a way that the radiation does not propagate in air beyond your range.

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