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Home > The Amp Hour Electronics Podcast > #446 – An Interview with Pete Bevelacqua


	Podcast:		The Amp Hour Electronics Podcast
	Episode:		#446 – An Interview with Pete Bevelacqua
	Category:		Science & Medicine
	Duration:		00:00:00
	Publish Date:		2019-06-09 23:44:27
	Description:		Welcome, Pete Bevelacqua of Antenna-Theory.com! This episode is brought to you by our sponsor Rohde & Schwarz. They just announced an industry first: complete solutions with all the upgrades up front—for one price. Now through December 31, save up to $10,000 on Rohde & Schwarz solution packages that come with fully loaded test & measurement instruments, right from the start. For more information about their latest product offering, check out AskAnEngineer.us Chris first met Pete when he was giving a talk at HDDG about a custom made VNA 0h 0m 55s Pete has been an antenna designer at Boeing, Apple, Nest 0h 1m 16s Pete got started in this because he really liked Electricity and Magnetism classes. 0h 2m 12s “Do I come out [of the class] and know how to put an antenna in a phone?” (answer: no) 0h 3m 4s Pete studied with Dr Bilanas at ASU 0h 3m 20s Convex optimization program 0h 4m 12s Used a lot in signal processing 0h 5m 38s Compared to linear optimizations 0h 6m 29s Boeing wanted to put 20 antennas on a plane 0h 7m 37s DC to daylight 0h 8m 20s Starting with a specific problem 0h 9m 43s “I want to put a bluetooth antenna in my device” 0h 9m 51s Start from a place of practicality 0h 11m 16s Do not make anything hard that doesn’t need to be hard 0h 11m 32s The one piece of math you need to know: the lowest frequency you’re using 0h 12m 52s Half wavelength for GPS is 3.5 inches 0h 13m 13s Efficiency is how much you’re putting in vs what you get out 0h 13m 30s Everything in RF is dB 0h 14m 49s …except for the antenna 0h 15m 13s “This meeting is 3dB too long” 0h 16m 35s Didn’t design antennas at Boeing because they didn’t need them to be custom/integrated 0h 18m 53s Directionality of antennae 0h 21m 6s “Do you want a high gain antenna?” 0h 21m 12s Gain specifically is the efficiency (in dB) plus the directivity (in dB) 0h 21m 52s FCC matters for consumer. If you have a directional antenna and it’s out of spec, you’ll need to take the overall power down 0h 23m 7s Effective Isotropic Radiated Power (EIRP) = conducted power + antenna gain 0h 24m 0s dDm is milliwatts of power 0h 24m 59s RF and antenna teams are different at hardware companies. 0h 26m 6s RF team assumes a 50 ohm antenna. The antenna team assumes a 50 ohm driver. 0h 27m 7s Went from Boeing to Apple 0h 28m 7s Consumer electronics and how it works 0h 29m 3s Industrial design team starts the process for look, feel and materials. 0h 29m 10s Mockup or simulation 0h 31m 36s Integration and understanding what will be interfering 0h 31m 58s Simulation is HFSS and CST 0h 33m 4s Pete isn’t big on simulating 0h 33m 16s Some people don’t simulate at all 0h 33m 57s Not that many types of antennas 0h 35m 3s Hybrids of dipoles 0h 36m 7s VNA 0h 36m 21s VSWR 0h 36m 37s VNA just tells you it is matched, not that it’s radiating 0h 37m 1s Once it’s matched you go about measuring its efficiency by putting it in an anechoic chamber 0h 37m 42s Dealing with multiple frequencies 0h 38m 30s GPS, Bluetooth, Wifi, Cellular 0h 38m 45s Cellular bands 0h 39m 5s Antennas are not meant to reject anything, that’s the job of the filters 0h 40m 20s 1850 (MHz) spectrum in cellular 0h 40m 35s “The ground in your PCB is part of your antenna” 0h 44m 20s How a flat antenna can create a unidirectional radiation 0h 46m 27s Omnidirectional is actually a donut pattern 0h 46m 46s For lower cellular frequencies, the phone is shorter than half the antenna 0h 47m 33s Explaining the polarization without looking 0h 48m 49s “The more volume you have the more bandwidth you have” 0h 50m 34s Fixing things with an exacto knife 0h 52m 34s Choking the lines allows you to select the frequencies 0h 54m 5s You start testing cert right away 0h 55m 23s Building your own VNA (talk at HDDG) 0h 56m 41s Went to Maker Faire, saw someone building a VNA 0h 57m 58s Need a bidirectional coupler 1h 0m 9s Need a frequency synthsizer 1h 1m 8s Coupler has directivity 1h 2m 24s Reflected comes back and you can measure with a chip 1h 3m 11s Got the Chazwazza (VNA project) on kickstarter, but the demand wasn’t there 1h 4m 0s The unit operates from 400 MHz to 2.7 GHz 1h 5m 4s Super light, especially compared to commercial equipment 1h 5m 16s After VNAs, testing chambers are also useful 1h 6m 36s Size of the chamber is a function of the wavelength 1h 6m 54s Pete’s current project is putting a working on putting a rocket in a balloon 1h 7m 56s Check out more of Pete’s work at Antenna-theory.com 1h 9m 53s
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