Mary Ann B. Meador and Felix A. Miranda

Glenn Research Center, Cleveland, Ohio

Design and Development of Aerogel-Based

Antennas for Aerospace Applications:

A Final Report to the NARI Seedling

NASA/TM—2014-218346

August 2014
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Mary Ann B. Meador and Felix A. Miranda

Glenn Research Center, Cleveland, Ohio

Design and Development of Aerogel-Based

Antennas for Aerospace Applications:

A Final Report to the NARI Seedling

NASA/TM—2014-218346

August 2014

National Aeronautics and

Space Administration

Glenn Research Center

Cleveland, Ohio 44135
Acknowledgments

The authors would like to thank Ms. Sarah Wright (California Institute of Technology Student Summer Intern), Ms. Elizabeth 

Barrios, Ms. Anna Sandberg, Ms. Emily MacMillon (all NASA Undergraduate Student Researcher Program), and Dr. Baochau 

N. Nguyen (GRC RHD/Senior Scientist, Ohio Aerospace Institute) for supporting the aerogel materials fabrication used in this 

work. Our thanks to Dr. Fred W. Van Keuls (GRC RHA/Vantage Partners, LLC), Dr. Carl H. Mueller (GRC RHA/Qinetiq NA), 

Ms. Elizabeth McQuaid (GRC FTF), Mr. Nicholas Varaljay (GRC FTF), and Dr. Rafael Rodríguez-Solís (GRC Summer Faculty 

Fellow, University of Puerto Rico-Mayagüez) for their support in the antenna simulations, fabrication and RF characterization. 

We are also thankful to Professor Maggie Chen, Texas State University-San Marcos, for the fabrication of the ink-jet printed slot

coupled patch antenna element investigated in this work. Finally, we want to express our gratitude to the Aerospace Research 

Mission Directorate (ARMD) Seedling Proposal Program for their support of this task.

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Trade names and trademarks are used in this report for identifi cation 

only. Their usage does not constitute an offi cial endorsement, 

either expressed or implied, by the National Aeronautics and 

Space Administration.

Level of Review: This material has been technically reviewed by technical management. 
NASA/TM—2014-218346 1 

Design and Development of Aerogel-Based Antennas for Aerospace 

Applications: A Final Report to the NARI Seedling 

Mary Ann B. Meador and Felix A. Miranda 

National Aeronautics and Space Administration 

Glenn Research Center 

Cleveland, Ohio 44135 

Abstract

As highly porous solids possessing low density and low dielectric permittivity combined with good 

mechanical properties, polyimide (PI) aerogels offer great promise as an enabling technology for 

lightweight aircraft antenna systems. While they have been aggressively explored for thermal insulation, 

barely any effort has been made to leverage these materials for antennas or other applications that take 

advantage of their aforementioned attributes. In Phase I of the NARI Seedling Project, we fabricated PI 

aerogels with properties tailored to enable new antenna concepts with performance characteristics (wide 

bandwidth and high gain) and material properties (low density, environmental stability, and robustness) 

superior to the state of practice (SOP). We characterized electromagnetic properties, including 

permittivity, reflectivity, and propagation losses for the aerogels. Simple, prototype planar printed circuit 

patch antennas from down-selected aerogel formulations were fabricated by molding the aerogels to net 

shapes and by gold-metalizing the pattern onto the templates via electron beam evaporation in a clean 

room environment. These aerogel based antennas were benchmarked against current antenna SOP, and 

exhibited both broader bandwidth and comparable or higher gain performance at appreciably lower mass. 

Phase II focused on the success of the Phase I results pushing the PI aerogel based antenna technology 

further by exploring alternative antenna design (i.e., slot coupled antennas) and by examining other 

techniques for fabricating the antennas including ink jet printing with the goal of optimizing antenna 

performance and simplifying production. We also examined new aerogel formulations with better 

moisture and solvent resistance to survive processing conditions. In addition, we investigated more 

complex antenna designs including passive phased arrays such as 2u4 and 4u8 element arrays to assess 

the scalability of the aerogel antenna concept. Furthermore, we explored the possibility of developing 

these arrays in thin, flexible form to make conformable antennas. 

Introduction 

The design and optimization of communication system technologies in support of aerospace platforms 

is of paramount interest in the aviation industry, for government (e.g., NASA, Department of Defense, etc.) 

and the commercial sector. Among the key technologies are transmit/receive (Tx/Rx) antennas required for 

communications (voice, high data rate video, internet, etc.) and navigation (GPS). A typical commercial 

and/or military aircraft (e.g., Boeing 737) could have as many as 15 to 100 antenna systems. This large 

number of antennas not only adds weight to the aircraft but also increases the complexity, and challenges 

the structural integrity of the fuselage. The latter is exacerbated in commuter and general aviation aircraft 

because of more limited space for antenna placement. Therefore approaches that could reduce the mass and 

number of antennas in the aforementioned aircraft and any other pertinent airborne platform (e.g., long 

duration, high altitude platforms) without sacrificing performance are highly desired. 

An innovative approach for lightweight antennas is to use aerogels which are highly porous solids 

with many interesting properties, including low density and low dielectric permittivity. The latter can 

reduce Radio Frequency (RF) losses and improve impedance matching in the antenna. In this project, we 

developed antennas incorporating a robust new form of polyimide aerogel developed at GRC to address 

 
NASA/TM—2014-218346 2 

Figure 1.—Polyimide aerogels developed at GRC. 

the challenges of reducing the mass and number of antennas, without sacrificing performance. The 

polyimide aerogels have superior mechanical strength over other types of aerogels and are easily 

fabricated into various forms as shown in Figure 1, making them suitable for this application. However, 

this project requires detailed knowledge of electromagnetic properties of the aerogels. 

Use of durable aerogels enables the design of lighter, wider bandwidth, higher gain, and even 

conformal antennas with potential for reduction of the number of antennas in aircraft and aeronautic 

platforms, reduction in mass and lower cost. The level of impact of mass savings will depend on antenna 

aperture size. Insertion of aerogels as components of planar printed circuit antennas will enable wider 

operational bandwidths, reduce the number of antenna apertures required to support communication 

requirements, and reduce discontinuities in the aircraft fuselage, the latter being more relevant for small 

general aviation aircraft and unmanned air vehicles (UAV). Flexible forms of aerogel may allow 

conformal, drag-free “wrap-able” antennas. In addition, Earth Science remote sensing applications from 

LEO/GEO telecommunication satellites can also benefit from this work, due to the advantages of using 

porous substrates in vacuum applications (less warping and out-gassing). The mass savings from fewer 

and lighter antennas could allow next generation aircraft/satellite designers to include additional payload 

electronics to enhance flying, navigation, and surveillance capabilities, or add more fuel to extend range 

or time aloft. The above is consistent with the ARMD goal for advances that improve aircraft and system 

efficiency. 

Approach and Results of Phase I 

Initially, in Phase I of the project, formulations of polyimide aerogels with different backbone 

chemistry were fabricated in sizes suitable for dielectric characterization at multiple bandwidths. RF 

characterization was performed to evaluate transmission and reflection properties, and electromagnetic 

losses at the operational frequencies of interest for polyimide aerogels. Formulations screened in the study 

include polyimide aerogels cross-linked with aromatic triamine, 1,3,5-tris(aminophenoxy)benzene (TAB) 

and made using two different dianhydrides and mixtures of two diamines as shown in Figure 2. The 

diamines chosen were 4,4ƍ-oxydianiline (ODA) and 2,2ƍ-dimethylbenzidine (DMBZ), and the 

dianhydrides used were biphenyl 3,3ƍ,4,4ƍ-tetracarbozylic dianhydride (BPDA) and 3,3ƍ,4,4ƍbenzophenone tetracarbozylic dianhydride (BTDA). The results of that study are summarized here but 

more details are available in Reference 1. 

The dielectric constants of several formulations from this study at three frequency ranges are shown 

in Figure 3. As seen in the figure, BTDA formulations all have higher dielectric constant than BPDA 

formulations. Other trends that can be seen by modeling the X-band data using multiple linear regression 

analysis include a decrease in dielectric with increasing DMBZ in the formulations (Ref. 1). However, the 

overarching trend is that the dielectric constant decreases with decreasing density of the aerogels no 

matter the formulation as shown in Figure 4. 
NASA/TM—2014-218346 3 

Figure 2.—Reaction scheme for synthesis of polymide aerogels from Phase I (Ref. 1). 
NASA/TM—2014-218346 4 

Figure 3.—Dielectric measurements at (a) X-Band, (b) Ka 

band, and (c) low frequency for various formulations of 

aerogels (average of two measurements) (Ref. 1). 

 
NASA/TM—2014-218346 5 

In all frequency ranges measured, dielectric constants track densities of the aerogels as shown in 

Figure 4, while the loss tangents are all pretty similar depending on frequency range. Based on these 

measurements, the polyimide formulation chosen for further study was a formulation made using 

100 percent DMBZ and BPDA. This formulation has the lowest dielectric constant, the best mechanical 

properties at the lowest density and good moisture resistance. 

Larger and thinner specimens of the aerogel were then fabricated for making the patch antenna. A 

schematic of the printed circuit patch antenna is shown in Figure 5. Figure 6 shows actual patch antennas 

fabricated using three different substrates: down-selected polyimide aerogel as well as the commercially 

available Rogers Duroid (Rogers Corporation) 6010 and 5880. The aerogel antenna was fabricated with 

both the antenna and ground plane deposited with e-beam evaporated gold. Note that the aerogel substrate 

did warp slightly on application of the gold coating. 

Figure 4.—Dielectric constants and loss tangents of polyimide aerogels graphed versus density (Ref. 1). 

Figure 5.—Schematic of printed circuit 

patch antenna on an aerogel substrate 

(Ref. 1). 

Figure 6.—Photograph of patch antenna on polyimide 

aerogel substrate (left), Rogers Duroid 6010 (İr = 10.2) 

(center); and Rogers Duroid 5880 (İr = 2.2)(right) (Ref. 1). 

 
NASA/TM—2014-218346 6 

Figure 7 shows a plot of the measured and simulated reflection coefficient scattering parameter (S11) 

versus frequency for the aerogel antenna compared to the Duroid antennas. Note that for all the antennas 

the experimental and simulated data correlate very well. 

A comparison of measured bandwidth and mass of the aerogel antennas with the Duroid antennas is 

shown in Figure 8. It is worthwhile to highlight that the aerogel antenna exhibits both broader bandwidth 

and lower mass than their Duroid counterparts. In fact, the Duroid 5880 which is closer in bandwidth to 

the aerogel antenna has a total mass which is an order of magnitude higher. These results reinforce the 

potential advantages of the aerogel based antennas (ABA) antennas for aerospace applications as 

originally proposed. 

Figure 7.—Plot of S11 versus frequency for experimental 

and simulated microstrip patch antennas fabricated from 

polyimide aerogel (100 percent DMBZ, BPDA, and TAB) 

and Rogers Duroid 6010 and 5880 (Ref. 1). 

Figure 8.—Comparison of (a) bandwidth (experimental and simulated), and (b) mass of antennas 

fabricated from polyimide aerogel, and Rogers Duroid 6010 and 5880 (Ref. 1). 
NASA/TM—2014-218346 7 

(a) 

(b) 

Figure 9.—(a) Printed circuit patch antennas mounted on GRC Far Field Antenna Range and (b) antenna 

gain versus scan angle from broadside. 

Antenna gain measurements were performed at the NASA Glenn Research Center Far Field Antenna 

Range using the substitution method according to the IEEE Standards Test Procedures for Antennas 

(Ref. 3). Figure 9 shows the antennas mounted in the aforementioned range and the gain versus scan 

angle from broadside. The gain of the aerogel antennas surpasses that of their Duroid counterparts. 

Accordingly, for the printed circuit patch antenna design considered in this study, the aerogel antennas 

exhibit lower mass, wider bandwidth and higher gain than similar designed antennas on state of practice 

microwave substrate laminates. 

Approach and Results of Phase II 

After the results of the initial study showed that only density of the polyimide aerogels and not 

backbone chemistry, seemed to affect dielectric constant, it was decided to test the use of fluorinated 

dianhydride, 2,2-bis(3,4-dicarboxyphenyl)hexafluoropropane dianhydride (6FDA), shown in Figure 10, in 

place of all or part of BPDA previously used in the polyimide backbone. It was thought that the 

fluorinated monomers should provide greater moisture resistance and possibly lower dielectric properties 

since fluorinated polyimides typically have lower dielectric constants than non-fluorinated backbone 

structures. Because of the lower reactivity of 6FDA, catalyst for chemical imidization had to be altered 

and optimized. Even so, it was not possible to obtain gels from 100 percent 6FDA. A study was 

performed to optimize the effect of 6FDA concentration from 0 to 50 percent of total dianhydride, 

oligomer length (n) from 10 to 30 repeat units, and total solids concentration from 7 to 10 wt% on 

properties of the aerogels. The results are summarized herein but more details of the study are available in 

Reference 2. 

Not surprisingly, reducing total solids concentration in the initial solution for gelation led to lower 

density aerogels as seen in Figure 11 (left). Increasing amount of 6FDA also led to lower density due to a 

decrease in the shrinkage that occurred during processing. As a measure of mechanical integrity, the 

compressive properties of the formulations were also evaluated. Figure 11 (right) shows the empirical 

model for modulus from compression, indicating the modulus decreases with decreasing solids 

concentration and increasing 6FDA fraction. Nevertheless, even the lowest modulus samples had modulus 

greater than 3 to 4 MPa. 

Duroid 6010 Duroid 5880 PI Aerogel 1 PI Aerogel 2
NASA/TM—2014-218346 8 

Figure 10.—Dianhydrides used in study. 

Figure 11.—Effect of variables on density (left) and modulus (right) (Ref. 2). 

Figure 12.—Effect of (left) 6FDA concentration, n and solids content on relative dielectric constant, and 

(right) relative dielectric constant plotted versus density (Ref. 2). 

The empirical model for relative dielectric constant of the PI aerogels in the experimental design is 

shown in Figure 12 (left). Dielectric constants ranged from 1.25 down to 1.08 for the lowest density 

samples. As seen in the graph, dielectric constant decreases with increasing 6FDA concentration and 

decreasing solids content. Interestingly, the empirical models for density and relative dielectric constant 

are nearly identical. This suggests that the dielectric properties are again dominated by density of the 

aerogel, regardless of the amount of fluorine content. Indeed, Figure 12 (right) shows dielectric constant 

plotted versus density, revealing a strong linear relationship independent of the amount of 6FDA used in 

the aerogels. Since the 6FDA containing aerogels tend to be less robust, the previous down selected 

formulation studied in Phase I with DMBZ and BPDA is still the better candidate for antennas. These 

results show that it too can be made with lower density by reducing solids concentration and it is expected 

that lower relative dielectric constants and better mechanical properties would be the result. 

0.05

0.10

0.15

0.20

0.25

10

15

20

25

30

0.0 0.1 0.2 0.3 0.4

Density, g/cm3

n

6FDA fraction

7% solids 

10 % solids

0

10

20

30

40

7

8

9

10

0.0 0.1 0.2 0.3 0.4

Compress vi e modu ul s, M

Pa

Polymer conc., wt %

6FDA fraction

1.05

1.10

1.15

1.20

1.25

1.30

10

15

20

25

30

0.0 0.1 0.2 0.3 0.4 Re al t vi e d ei el ctr ci cons at nt, x-band

n

6FDA fraction

7 %

10 %

Density, g/cm3

0.05 0.10 0.15 0.20 0.25

Relative dielectric constant, x-band

1.05

1.10

1.15

1.20

1.25

1.30

1.35
NASA/TM—2014-218346 9 

Antenna Fabrication and Testing in Phase II 

The typical photolithography process requires exposing the PI aerogels to a series of solutions (both 

aqueous and organic). Because of the highly porous nature of the aerogels (90 to 97 percent porosity), it 

has not yet been possible to avoid the absorption of these solutions into the aerogel during the process. As 

an alternative, we have examined the potential of using ink jet printing of the antenna patterns on the 

aerogel. While initial attempts resulted in a poorly printed patch with bleeding around the edges, refined 

techniques resulted in a good quality patch, shown in Figure 13. This antenna exhibited gain values of 

4.5 and 7.7 dBi at 4.4 and 5.0 GHz, respectively, which are comparable to those obtained with the e-beam 

evaporation approach. Hence, this technique could offer a viable alternative for the fabrication of 

antennas on aerogels or other substrates sensitive to the processing steps of standard chemical 

photolithography techniques. 

While there are a variety of approaches to develop phased array antennas, for the purpose of this 

study we have selected the slot coupled design approach (Ref. 4). In general, the slot coupled approach 

facilitates the integration of beam shaping elements such as phase shifters and attenuators as well as 

power amplifiers (i.e., low noise for receive and high gain for transmit) into the antenna feed network. 

These components are essential for electronically steerable adaptively controlled antennas. Accordingly, 

we have selected the slot coupled approach to demonstrate aerogel-based phased array antennas. 

Figure 14 shows a picture of a 2u4 phased array antenna on a PI aerogel substrate. The gold printed 

circuit patches of the phased array were deposited using e-beam evaporation. 

Figure 13.—Ink jet printed slot 

coupled patch antenna using 

an aerogel substrate. 

Figure 14.—E-beam evaporated 2u4 slot coupled aerogel antenna 

array with feed network (left); array under test at GRC’s Cylindrical 

Near Field Antenna Range Facility (right). 

 
NASA/TM—2014-218346 10 

Figure 15 shows the experimental and simulated H-plane and the E-plane gain data for this array at 

5.0 GHz. The experimental and simulated results are in close agreement, indicating that this configuration 

can be scaled to larger arrays. As shown in Figure 16, a comparison of the performance of 2u4 phased 

arrays fabricated on aerogel and Duroid 5880 (İr = 2.2) substrates shows that the aerogel antenna gain is 

more than 1 dB higher than its Duroid counterpart (17.6 versus 16.3, respectively). Also, the mass savings 

of the aerogel array are substantial as shown in Table I. 

Figure 15.—Gain versus angle from bore sight for a 4u2 slot coupled aerogel 

antenna array. Aperture size is 15.3u5.8 cm.

Figure 16.—Comparison of gain versus angle from bore sight for 2u4 slot coupled 

aerogel and Duroid (5880) arrays. 

TABLE I.—MASS COMPARISON BETWEEN 2u4 AEROGEL ANTENNA 

AND ITS DUROID COUNTERPART 

Item Aerogel Duroid 

Radiator tile only 5.8 g (3.68 mm thick) 88.1 g (3.18 mm thick) 

Feed network and ground plane (i.e., 10 mil) 

Duroid with copper metallization) 

13.9 g 14.4 g 

SMA connector weight 3.9 g (male) 1.3 g (female) 

Total antenna weight 23.6 g 103.8 g 

 

-20

-15

-10

-5

0

5

10

15

20

-40 -20 0 20 40

experimental

simulated

maximum experimental

gain = 17.6 dBi

H-plane

co-polarization

5000 MHz

antenna gain, dBi

angle from boresight, degrees

-5

0

5

10

15

20

-40 -30 -20 -10 0 10 20 30 40

experimental

simulated

maximum experimental

gain = 17.6 dBi

H-plane

co-polarization

5000 MHz

antenna gain, dBi

angle from boresight, degrees

-20

-15

-10

-5

0

5

10

15

20

-40 -20 0 20 40

aerogel

duroid

maximum 

experimental

gains:

aerogel=17.6 dBi

duroid = 16.3

H-plane

co-polarization

5000 MHz

antenna gain, dBi

angle from boresight, degrees

-5

0

5

10

15

20

-40 -30 -20 -10 0 10 20 30 40

aerogel

duroid

maximum 

experiment al

gains :

aerogel=17.6 dBi

duroid = 16.3

E-plane

co-polarization

5000 MH z

antenna gain, dBi

angle from boresight, degrees
NASA/TM—2014-218346 11 

To further demonstrate the scalability of the aerogel phased arrays, a 32 element phased array made 

of four 2u4 aerogel tiles was fabricated. Figure 17 shows the array mounted for testing in GRC’s 

Cylindrical Near Field Antenna Range. 

Figure 18 shows the experimental and modeled H-plane and the E-plane gain for this array at 

5.0 GHz. The measured gain is consistent with a uniformly illuminated aperture. As shown in Figure 19, 

the aerogel antennas surpass the Duroid counterpart in sustained gain over bandwidth and aperture 

efficiency. 

Figure 17.—E-beam evaporated 

32 element slot coupled aerogel 

antenna comprised of four 2u4 

element arrays. 

Figure 18.—Gain versus angle from boresight for a 32 element array. Total aperture size is 

32.9u13.9 cm. 

Figure 19.—Antenna gain and aperture efficiency for aerogel and Duroid antenna arrays. 

 

-20

-10

0

10

20

-40 -20 0 20 40

experimental

simulated

antenna gain, dBi

ang le f rom bo re s igh t, d egrees

max imum ex perimental

gain = 21.9 dBi

H -plane

co-polarization

5000 MHz

-20

-10

0

10

20

-40 -30 -20 -10 0 10 20 30 40

experimental

simulated

antenna gain, dBi

angle f rom bores ight, degrees

max imum 

ex perimental

gain = 21.9 dBi

E-plane

co-polarization

5000 MHz
NASA/TM—2014-218346 12 

Figure 20.—Experimental set-up for EVM measurements. 

To validate the usage of the aerogel phased array antennas for practical applications, a terrestrial 

line-of-sight (LOS) experiment was performed to investigate the suitability of the antennas to support 

digital communication links. The test was performed using typical modulation schemes such as 

Quadrature Phase Shift Keying (QPSK) and ʌ/4-Differential Quadrature Phase Shift Keying 

(ʌ/4-DQPSK). The integrity of the link was evaluated by performing Error Vector Magnitude (EVM) 

measurements which provide information on the extent to which experimental parameters associated with 

the quality of the link values deviate from reference link values. The experimental set-up for the EVM 

consisted of two identical 2u4 aerogel phased array antennas, one used as the transmit antenna and the 

other as the receive antenna, the antennas were separated by a distance of 8.5 m as shown in Figure 20. 

The aforementioned separation satisfies the 2D2

/Ȝ far field criteria, where D is the maximum antenna 

aperture dimension and Ȝ is the wavelength corresponding to the design frequency of the phased array. 

For the case under consideration D-16.1 cm, Ȝ = 6.0 cm and 2D2

/Ȝ = 0.864 m. 

Figure 21 shows constellation graphs summarizing the performance of the 2u4 aerogel phased array 

antenna in the terrestrial link experiment using the aforementioned modulation schemes. The experiment 

was performed at a carrier frequency = 5.0 GHz; symbol rate = 7 Msps; and data rate = 14 Mbps. Also to 

overcome the instrumentation limitations posed by the spectrum analyzer used in this test an Avantek 

amplifier (AWT-6053) was placed between Rx antenna and spectrum analyzer. 

Note that as the transmitted power decreases, the power received at the aerogel antenna decreases, the 

EVM increases and the signal-to-noise ratio (SNR) decreases. However, even at the lowest transmitted 

and received power levels for each of the modulation schemes, the constellation of points is still 

discernible indicating a viable digital communication link. The EVM measurements provide close 

approximation of signal to noise demodulated signal from which the bit-error-rate of the signal can be 

calculated. Figure 22 shows plots of EVM and SNR versus for transmitted power for the aerogel phased 

array at 5.0 GHz. It is worthwhile to mention that when performing EVM of the phased array 4.6 GHz 

and 5.4 GHz (i.e., r0.4 GHz away from the optimal operational frequency of the antenna) the antennas 

maintained communications links with approximately 2.0 dB loss relative to the performance at 5.0 GHz. 

These results are very encouraging not only for communications but also for radar applications where the 

wide operational frequency range would be very useful. 
NASA/TM—2014-218346 13 

Carrier frequency = 5.0 GHz; Symbol rate = 7 Msps; data rate = 14 Mbps; Avantek amplifier 

(AWT-6053) between Rx antenna and spectrum analyzer. Small signal gain = 27 dB; Noise figure a4 dB 

Figure 21.—Verification of antenna performance in the terrestrial link. 

Figure 22.—EVM and SNR versus transmitted power at 5.0 GHz for the aerogel antennas. 

 
NASA/TM—2014-218346 14 

Based on the results discussed above we also explored the possible data rates that could be enabled 

using the 2u4 aerogel phased array antennas in several relevant communication link scenarios such as 

commercial aircraft to ground, unmanned air vehicles (UAV) to ground, and cubesats to ground as shown 

in Figure 23. For these scenarios we considered the following: transmit and received 2u4 element aerogel 

phased array antennas at 5.0 GHz and with a gain of 15.6 dBi; transmit power = 2 W; receiver noise 

figure = 4 dB; QPSK modulation scheme; signal-to-noise ratio t 14 dB; bit-error-rate (BER) d 10–6; no 

coding gain; and receiver implementation losses = 3 dB. Table II shows the data rate results when the 

aforementioned vehicles are 10q above the horizon (i.e., close to worst case scenario regarding free space 

losses). When the vehicles are directly overhead the free space losses are reduced by 7.5 dB and therefore 

the allowable date rates are 5.7 times higher than when the vehicle is near the horizon. Note that the date 

rates shown are enough to support voice and data (cubesat to ground case) and voice, data and video 

(UAV and commercial aircraft cases), which demonstrate the suitability of the aerogel phased array 

antennas to address communications requirements in these and similar platforms. 

Figure 23.—Different aerospace link scenarios that 

could be supported by aerogel antennas. The 

indicated distances correspond to typical elevations 

when the vehicles are right overhead; i.e., at zenith. 

TABLE II.—DATA RATES FOR SEVERAL AEROSPACE VEHICLES FOR 

ELEVATIONS 10q ABOVE THE HORIZON 
NASA/TM—2014-218346 15 

Major Findings and Conclusions 

The use of novel aerogel materials as substrates for radio frequency (RF) antennas has been 

investigated. Optimized aerogel formulations led to lower dielectric properties, better moisture/solvent 

resistance, and better mechanical properties. We have demonstrated the feasibility of fabricating printed 

circuit antennas on optimized Polyimide aerogel materials either by e-beam evaporation or ink-jet printed 

techniques. The performance of single-patch and phased array aerogel antennas was demonstrated with 

both configurations exhibiting notable advantages in mass, bandwidth, and gain over typically used 

microwave substrate laminates (e.g., Duroid). The aerogel antennas were demonstrated both in thick as 

well as thin substrates, suggesting that the attributes of PI aerogels could be maximally exploited at S- or 

C-band frequencies where the large physical dimensions of the antennas offer the opportunity for tailoring 

the array parameters (i.e., radiator size, substrate thickness, etc.) to provide optimal gain, broad bandwidth 

and low mass as compared to typically used microwave laminate substrates. Higher frequencies aerogel 

antennas could be suitable for aerospace applications requiring low profile for drag reduction and that 

could benefit from conformal, low profile, and reduce complexity in design offered by the aerogel 

antennas studied in this work. Finally, demonstration of digital communication links using common 

modulation schemes (e.g., QPSK and ʌ/4-DQPSK) that could be used to support voice, data and video 

communication links in a variety of aerospace platforms such as UAV, commercial aircraft, and cubesats. 

References 

1. Meador M.A.B., Wright S., Sandberg A., Nguyen B.N., Van Keuls F.W., Mueller C H, RodríguezSolís R., and Miranda F.A. “Low Dielectric Polyimide Aerogels As Substrates for Lightweight Patch 

Antennas,” ACS Applied Materials and Interfaces, 4: 6346í6353, 2012. 

2. Meador M.A.B., McMillon E, Sandberg A., Barrios E., Wilmoth N.G., Mueller C.H., and Miranda 

F.A. “Dielectric and Other Properties of Polyimide Aerogels Containing Fluorinated Blocks,” ACS 

Applied Materials and Interfaces, 6: ASAP, 2014. 

3. “IEEE Standard Test Procedures for Antennas,” ANSI/IEEE Std 149í1779, 1979. 

4. “Microstrip Antennas,” Chapter 14, in “Antenna Theory; Analysis and Design,” 2nd Ed., by 

Constantine A. Balanis, (John Wiley & Sons, Inc. 1997).