IEEE - Aerospace and Electronic Systems - November 2019 - 22

Additively Manufactured Luneburg Retroreflector

Figure 1.
Propagation of power through Luneburg lens retroreflector.

Figure 4.
Illustration of the FDM layer-by-layer printing process of the
Luneburg lens retroreflector using space filling curves.

Figure 2.
Space-filling geometry used for generating spatially varying
permittivities. By varying the number of turns the local volume
fraction of printed material, and thus its effective permittivity, is
controlled. Unit cells are stacked in rows and columns such that a
layer is spatially graded using a single continuous curve.

Figure 5.
View of the copper tape placed over the spherical end cap of the
reflector.

The final lens was 120 mm diameter with its unit cells specifically tailored for operation over frequencies that range
from 8-30 GHz.
Upon completion of the AM process, a set of copper
tape strips were overlapped onto the rear hemisphere of
the lens to create a simple end-cap reflecting surface. The
device and end-cap structure can be seen in Figure 5.

Figure 3.
Free-space focused beam measurement system.

lens is illustrated in Figure 4. As shown in the figure, a low
permittivity ð"r < 1:1Þ support base was added to enable
the fabrication of the lens in a single print run. It is very challenging to FDM print a spherical geometry without support.
The low permittivity base serves this purpose. It was found
through simulations and experiments that the low permittivity base did not greatly affect the EM properties of the lens.
22

RCS MODELING METHODOLOGY
High-frequency structure simulator (HFSS) was used for
electromagnetic modeling and simulations. HFSS predicted a full 360 RCS measurements for the fabricated
lens at the various frequency bands. The simulated model

IEEE A&E SYSTEMS MAGAZINE

NOVEMBER 2019



IEEE - Aerospace and Electronic Systems - November 2019

Table of Contents for the Digital Edition of IEEE - Aerospace and Electronic Systems - November 2019

Contents
IEEE - Aerospace and Electronic Systems - November 2019 - Cover1
IEEE - Aerospace and Electronic Systems - November 2019 - Cover2
IEEE - Aerospace and Electronic Systems - November 2019 - Contents
IEEE - Aerospace and Electronic Systems - November 2019 - 2
IEEE - Aerospace and Electronic Systems - November 2019 - 3
IEEE - Aerospace and Electronic Systems - November 2019 - 4
IEEE - Aerospace and Electronic Systems - November 2019 - 5
IEEE - Aerospace and Electronic Systems - November 2019 - 6
IEEE - Aerospace and Electronic Systems - November 2019 - 7
IEEE - Aerospace and Electronic Systems - November 2019 - 8
IEEE - Aerospace and Electronic Systems - November 2019 - 9
IEEE - Aerospace and Electronic Systems - November 2019 - 10
IEEE - Aerospace and Electronic Systems - November 2019 - 11
IEEE - Aerospace and Electronic Systems - November 2019 - 12
IEEE - Aerospace and Electronic Systems - November 2019 - 13
IEEE - Aerospace and Electronic Systems - November 2019 - 14
IEEE - Aerospace and Electronic Systems - November 2019 - 15
IEEE - Aerospace and Electronic Systems - November 2019 - 16
IEEE - Aerospace and Electronic Systems - November 2019 - 17
IEEE - Aerospace and Electronic Systems - November 2019 - 18
IEEE - Aerospace and Electronic Systems - November 2019 - 19
IEEE - Aerospace and Electronic Systems - November 2019 - 20
IEEE - Aerospace and Electronic Systems - November 2019 - 21
IEEE - Aerospace and Electronic Systems - November 2019 - 22
IEEE - Aerospace and Electronic Systems - November 2019 - 23
IEEE - Aerospace and Electronic Systems - November 2019 - 24
IEEE - Aerospace and Electronic Systems - November 2019 - 25
IEEE - Aerospace and Electronic Systems - November 2019 - 26
IEEE - Aerospace and Electronic Systems - November 2019 - 27
IEEE - Aerospace and Electronic Systems - November 2019 - 28
IEEE - Aerospace and Electronic Systems - November 2019 - 29
IEEE - Aerospace and Electronic Systems - November 2019 - 30
IEEE - Aerospace and Electronic Systems - November 2019 - 31
IEEE - Aerospace and Electronic Systems - November 2019 - 32
IEEE - Aerospace and Electronic Systems - November 2019 - 33
IEEE - Aerospace and Electronic Systems - November 2019 - 34
IEEE - Aerospace and Electronic Systems - November 2019 - 35
IEEE - Aerospace and Electronic Systems - November 2019 - 36
IEEE - Aerospace and Electronic Systems - November 2019 - 37
IEEE - Aerospace and Electronic Systems - November 2019 - 38
IEEE - Aerospace and Electronic Systems - November 2019 - 39
IEEE - Aerospace and Electronic Systems - November 2019 - 40
IEEE - Aerospace and Electronic Systems - November 2019 - 41
IEEE - Aerospace and Electronic Systems - November 2019 - 42
IEEE - Aerospace and Electronic Systems - November 2019 - 43
IEEE - Aerospace and Electronic Systems - November 2019 - 44
IEEE - Aerospace and Electronic Systems - November 2019 - 45
IEEE - Aerospace and Electronic Systems - November 2019 - 46
IEEE - Aerospace and Electronic Systems - November 2019 - 47
IEEE - Aerospace and Electronic Systems - November 2019 - 48
IEEE - Aerospace and Electronic Systems - November 2019 - 49
IEEE - Aerospace and Electronic Systems - November 2019 - 50
IEEE - Aerospace and Electronic Systems - November 2019 - 51
IEEE - Aerospace and Electronic Systems - November 2019 - 52
IEEE - Aerospace and Electronic Systems - November 2019 - 53
IEEE - Aerospace and Electronic Systems - November 2019 - 54
IEEE - Aerospace and Electronic Systems - November 2019 - 55
IEEE - Aerospace and Electronic Systems - November 2019 - 56
IEEE - Aerospace and Electronic Systems - November 2019 - 57
IEEE - Aerospace and Electronic Systems - November 2019 - 58
IEEE - Aerospace and Electronic Systems - November 2019 - 59
IEEE - Aerospace and Electronic Systems - November 2019 - 60
IEEE - Aerospace and Electronic Systems - November 2019 - 61
IEEE - Aerospace and Electronic Systems - November 2019 - 62
IEEE - Aerospace and Electronic Systems - November 2019 - 63
IEEE - Aerospace and Electronic Systems - November 2019 - 64
IEEE - Aerospace and Electronic Systems - November 2019 - 65
IEEE - Aerospace and Electronic Systems - November 2019 - 66
IEEE - Aerospace and Electronic Systems - November 2019 - 67
IEEE - Aerospace and Electronic Systems - November 2019 - 68
IEEE - Aerospace and Electronic Systems - November 2019 - 69
IEEE - Aerospace and Electronic Systems - November 2019 - 70
IEEE - Aerospace and Electronic Systems - November 2019 - 71
IEEE - Aerospace and Electronic Systems - November 2019 - 72
IEEE - Aerospace and Electronic Systems - November 2019 - 73
IEEE - Aerospace and Electronic Systems - November 2019 - 74
IEEE - Aerospace and Electronic Systems - November 2019 - 75
IEEE - Aerospace and Electronic Systems - November 2019 - 76
IEEE - Aerospace and Electronic Systems - November 2019 - Cover3
IEEE - Aerospace and Electronic Systems - November 2019 - Cover4
https://www.nxtbook.com/nxtbooks/ieee/aerospace_december2023
https://www.nxtbook.com/nxtbooks/ieee/aerospace_november2023
https://www.nxtbook.com/nxtbooks/ieee/aerospace_october2023
https://www.nxtbook.com/nxtbooks/ieee/aerospace_september2023
https://www.nxtbook.com/nxtbooks/ieee/aerospace_august2023
https://www.nxtbook.com/nxtbooks/ieee/aerospace_july2023
https://www.nxtbook.com/nxtbooks/ieee/aerospace_june2023
https://www.nxtbook.com/nxtbooks/ieee/aerospace_may2023
https://www.nxtbook.com/nxtbooks/ieee/aerospace_april2023
https://www.nxtbook.com/nxtbooks/ieee/aerospace_march2023
https://www.nxtbook.com/nxtbooks/ieee/aerospace_february2023
https://www.nxtbook.com/nxtbooks/ieee/aerospace_january2023
https://www.nxtbook.com/nxtbooks/ieee/aerospace_december2022
https://www.nxtbook.com/nxtbooks/ieee/aerospace_november2022
https://www.nxtbook.com/nxtbooks/ieee/aerospace_october2022
https://www.nxtbook.com/nxtbooks/ieee/aerospace_september2022
https://www.nxtbook.com/nxtbooks/ieee/aerospace_august2022
https://www.nxtbook.com/nxtbooks/ieee/aerospace_july2022
https://www.nxtbook.com/nxtbooks/ieee/aerospace_june2022
https://www.nxtbook.com/nxtbooks/ieee/aerospace_may2022_tutorial
https://www.nxtbook.com/nxtbooks/ieee/aerospace_may2022
https://www.nxtbook.com/nxtbooks/ieee/aerospace_april2022
https://www.nxtbook.com/nxtbooks/ieee/aerospace_march2022
https://www.nxtbook.com/nxtbooks/ieee/aerospace_february2022
https://www.nxtbook.com/nxtbooks/ieee/aerospace_january2022
https://www.nxtbook.com/nxtbooks/ieee/aerospace_december2021
https://www.nxtbook.com/nxtbooks/ieee/aerospace_november2021
https://www.nxtbook.com/nxtbooks/ieee/aerospace_october2021
https://www.nxtbook.com/nxtbooks/ieee/aerospace_september2021
https://www.nxtbook.com/nxtbooks/ieee/aerospace_august2021
https://www.nxtbook.com/nxtbooks/ieee/aerospace_july2021
https://www.nxtbook.com/nxtbooks/ieee/aerospace_june2021
https://www.nxtbook.com/nxtbooks/ieee/aerospace_may2021
https://www.nxtbook.com/nxtbooks/ieee/aerospace_april2021
https://www.nxtbook.com/nxtbooks/ieee/aerospace_march2021
https://www.nxtbook.com/nxtbooks/ieee/aerospace_march2021_tutorials
https://www.nxtbook.com/nxtbooks/ieee/aerospace_february2021
https://www.nxtbook.com/nxtbooks/ieee/aerospace_january2021
https://www.nxtbook.com/nxtbooks/ieee/aerospace_november2020
https://www.nxtbook.com/nxtbooks/ieee/aerospace_december2020
https://www.nxtbook.com/nxtbooks/ieee/aerospace_october2020
https://www.nxtbook.com/nxtbooks/ieee/aerospace_september2020
https://www.nxtbook.com/nxtbooks/ieee/aerospace_august2020
https://www.nxtbook.com/nxtbooks/ieee/aerospace_july2020
https://www.nxtbook.com/nxtbooks/ieee/aerospace_june2020
https://www.nxtbook.com/nxtbooks/ieee/aerospace_may2020
https://www.nxtbook.com/nxtbooks/ieee/aerospace_april2020
https://www.nxtbook.com/nxtbooks/ieee/aerospace_march2020
https://www.nxtbook.com/nxtbooks/ieee/aerospace_february2020
https://www.nxtbook.com/nxtbooks/ieee/aerospace_january2020
https://www.nxtbook.com/nxtbooks/ieee/aerospace_december2019
https://www.nxtbook.com/nxtbooks/ieee/aerospace_october2019partII
https://www.nxtbook.com/nxtbooks/ieee/aerospace_november2019
https://www.nxtbook.com/nxtbooks/ieee/aerospace_october2019
https://www.nxtbook.com/nxtbooks/ieee/aerospace_july2019
https://www.nxtbook.com/nxtbooks/ieee/aerospace_september2019
https://www.nxtbook.com/nxtbooks/ieee/aerospace_august2019
https://www.nxtbook.com/nxtbooks/ieee/aerospace_june2019
https://www.nxtbook.com/nxtbooks/ieee/aerospace_april2019
https://www.nxtbook.com/nxtbooks/ieee/aerospace_may2019
https://www.nxtbook.com/nxtbooks/ieee/aerospace_march2019
https://www.nxtbook.com/nxtbooks/ieee/aerospace_december2018
https://www.nxtbook.com/nxtbooks/ieee/aerospace_august2018
https://www.nxtbook.com/nxtbooks/ieee/aerospace_october2018
https://www.nxtbook.com/nxtbooks/ieee/aerospace_september2018
https://www.nxtbook.com/nxtbooks/ieee/aerospace_november2018
https://www.nxtbookmedia.com