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Re: [Amps] worthwhile patents on RF amplifiers?

To: amps@contesting.com
Subject: Re: [Amps] worthwhile patents on RF amplifiers?
From: "Roger (K8RI)" <k8ri@rogerhalstead.com>
Date: Mon, 15 Feb 2016 23:28:34 -0500
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I'm no expert on patents although I learned more than I wanted with the company I worked for. Most of their products were based on a propitiatory process and not patented. The rational was that without the patent information present, the gamble was no one would figure out the rather simple process. It worked and no knockoffs turned up in over 50 years. Far longer than the patent system of the day would have offered protection.
Somewhere around 50 years, another company finally figured it out, won a 
patent, got greedy, and sued us for 50 years of patent infringement. It 
came out that we had been doing this for 50 years and they lost the case 
and patent.  Now anyone who figures it out can make the stuff as it went 
from an expensive product to a relative inexpensive commodity.  That was 
under the old system, now it's first to patent something, but if it can 
be shown they are holding a patent on a process, algorithm, or product 
that has been commonly used , configured, or produced, then they will 
lose the patent.
Under the new system, we would likely have lost the case and the 
settlement would likely been in the Billions..
The following is what I believe and may be right or wrong.
I don't know if you even need to prove it works, or produce a working model.under the new system It has paved the way for companies that purchase patents and vigorously pursue, or defend those patents. I've forgotten the name for such slime. They have no facilities, no devices, generally nothing but the patents. It started a whole new industry.
These hold until someone with enough money to see it through the courts 
for at least several levels, or prove to the USPO their claim is bogus.. 
These places have relatively little invested and hold a LOT of cash, so 
they can hang in there unless the patent is invalidated on the first 
challenge.
In this case, perhaps a Handbook, or few old magazines that predate 
their application would be enough.
73

Roger (K8RI)


On 2/12/2016 Friday 7:13 PM, jtml@losalamos.com wrote:
I was looking through some recent solid state RF amplifier patents, and 2 stood out for comment here. You may be able to view these or at least the cover sheet and abstracts with online free patent viewers now that you have these numbers:
US0285168 was awarded by the USPO around Dec. of 2007, invented by 
Steven Dishop of Bellefontaine, OH. The address is given Pearce and 
Gordon LLP in Cleveland. In it claims are made for a solid state 
module that has push pull MOSFETs operating at least 200 watts and 50 
volts. An input and output transformer or balun is used to convert 
single ended to balanced for the transistors and match (1:4 on 
output). Then there is a claim for a four FET similar amplifier where 
a pair of FETs are operated in push pull, with drains tied together, 
and these are then operated push pull with another similar par, driven 
out of phase with the first. This one is 400 watts. I don't understand 
what is unique about any of this, and have seen similar amplifier 
constructions for decades. How can this patent hold valid?
The second one, US5187580, assigned to Advanced Energy Industries in 
Ft Collins (a real RF company, BTW) was awarded in Feb. of 1993. In 
this one the inventors suggest making a single ended MOSFET class E 
amplifier that works better without a shunt capacitor across D to S of 
the output device. They claim that the varactor capacitance of the Cds 
alone is sufficient, even better, and that the larger devices can be 
made to work at higher power and frequencies this way. Multi-kilowatts 
and 65 MHz. Normally in class E the voltage at the device is forced to 
zero before it switches, in this one it switches with substantial 
voltage across it, even suggests this is better. I don't see mention 
of improved efficiency with this technique, just very high power 
availability. Something bothersome is the claim that it must operate 
in a different class than A, B, AB, C, D, E, F...but no real math or 
proof of anything other than a suboptimal class E. Its the first RF 
amplifier patent I have seen where the invention is of a strange 
performance without sufficient explanation. Maybe I am being stupid 
and should just take these at face value? One has to wonder if their 
wattmeters were tricked, or harmonics were excessive, or whatever. 
None of this is described.
Solid state RF amplifier experts, chime in!

73
John
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