ELEC 332

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Background

Although Part 15 allows unlicensed operation at almost any frequency in the spectrum, in most cases the allowed power is so small that the maximum range is only a few meters. An exception to this is to be found in the set of frequencies called the Industrial, Scientific, and Medical (ISM) Bands. In these bands powers ranging from 10s of miliwatts to several watts are allowed. If you have an interesting application that you want to investigate, one of these bands is an obvious place to try it out.

Economical test equipment is available for HF and VHF frequencies, but the ISM bands in this range are fairly narrow. More interesting are the higher ISM frequencies, e.g. the 900 MHz, 2.4 GHz, and 5 GHz bands. Unfortunately, commercial equipment for these frequencies is extremely expensive. However, the popularity of these bands for commercial applications has brought about the availability of a variety of high frequency integrated circuits at very low prices. These could be used to build instruments which, although not as accurate as expensive laboratory equipment, nevertheless provides useful functionality at a much lower price.

Description

Although there are many different types of RF instruments available (e.g. signal generators, power meters, spectrum analyzers, frequency counters, network analyzers, antenna analyzers, etc.), most can be assembled from various combinations of controlled sources and calibrated receivers.

Specifications

Almost any level of functionality has some utility, but the more accuracy, sensitivity, range, etc. that your instrument has, the more useful it is. And of course the more expensive. Choose a balance of cost and performance that will achieve a satisfactory market for your product. Here are some example specifications:

Frequency Range.

Obviously must include at least one ISM band. 49 Mhz and below are already well addressed by existing products, although significantly lower price or increased functionality in a single package could produce a viable product. (A 15 kHz to 150 MHz combination signal generator, spectrum analyzer, and network analyzer for under $1000 would be a really hot item.) There are no US ISM bands between 49 and 900 MHz, although there are several amateur radio bands in this range.

Also, there are no US ISM bands between 5 GHz and 24 GHz. 24 GHz is more of a challenge than we are equipped to take on. In fact 5 GHz is probably on the boundary of what we should attempt.