1. Electronically Steered Antennas
Yoel Gat, CEO
SatixFy

2. Outline Defining the scope Why electrically steering antenna?
How to electronically steer a beam?
Phased array antennas advantages & disadvantages
True Time Delay (TTD) antenna basics
Loss due to pointing error
Types of electrically Steered antennas
TTD & ESMA technology
Summary: Phased Array Vs. True Time Delay

3. Defining the scope of the presentation
Real Electronically Steered Antennas (no moving parts)
Solutions that can be demonstrated today (paper products are always better…)
Satellite solutions (not 5G)
Technologies
Analog Phase Shifters
Metamaterial
Digital Beam Forming (True Time Delay)
Challenges
Power
Price (lots of electronics – hence silicon is a necessity)
Calibration (frequency, temperature, scan angles, aging)
End-to-End Full system requirement, including modems on both ends

4. Why Electronically Steering Antenna?
No moving parts

5. Why Electronically Steering Antenna?
No moving parts
Low profile

6. Why Electronically Steering Antenna?
No moving parts
Low profile
Can be conformal

7. Why Electronically Steering Antenna?
No moving parts
Low profile
Can be conformal
Facilitates multibeam

8. Why Electronically Steering Antenna?
No moving parts
Low profile
Can be conformal
Facilitates multibeam
Self pointing

9. Why Electronically Steering Antenna?
No moving parts
Low profile
Can be conformal
Facilitates multibeam
Self pointing
Adaptive directivity

10. Why Electronically Steering Antenna?
No moving parts
Low profile
Can be conformal
Facilitates multibeam
Self pointing
Adaptive directivity
“All in one“ solution

11. Why Electronically Steering Antenna?
No moving parts
Low profile
Can be conformal
Facilitates multibeam
Self pointing
Adaptive directivity
“All in one“ solution
And this just ground satellite segment …

12. How to Electronically Steer a Beam? True Time Delay (TTD) Basics

13. Parabolic Antenna
A parabolic antenna is physically designed so the wavefront from the boresight direction will be combined coherently (same delay)

14. Parabolic Antenna (cont.)
Wavefronts from other direction will not be coherently combined (different delays)

15. Flat Panel Antenna
A flat panel antenna coherently combines the boresight wavefront
Antenna patch

16. Flat Panel Antenna (cont.)
Here too, wavefronts from other directions experience different delays (green arrows) and will not be coherently combined

17. Delay Lines
If we can add delay lines that compensate the delays that results from the non boresight direction…
Could be implement by phase shifter (approximation of true time delay – at a certain frequency…)
Or by True Time Delay (Digital Beam Forming)

18. Phased Array vs. True Time Delay (TTD) Signal Bandwidth: Different Scan Angles for Different Frequencies!
𝑓 𝑐
𝑓 𝑐 −𝑓 𝐵
𝑓 𝑐 +𝑓 𝐵 20 19 21
freq (GHz)
Antenna defocused
(Beam Squint)
𝑦 𝐵 𝑡 = 𝑛=0 𝑁−1 𝑦 𝑛 𝑡 exp −𝑗 𝜑 𝑛
𝑦 𝐵 𝑡 = 𝑛=0 𝑁−1 𝑦 𝑛 𝑡− 𝜏 𝑛 exp −𝑗 𝜑 𝑛

19. Phased Array Antennas Advantages & Disadvantages

20. Phased Array Antennas Main Advantages
Low power
Some implementations are passive
Low cost
One phase shifter per antenna patch
Common RF chain

21. Phased Array Antennas Main Disadvantages
Low resolution (beam steering jumps by a few degrees)
Typically switching of constant phase shifters

22. Phased Array Antennas Main Disadvantages
Low resolution (beam steering jumps by a few degrees)
Typically switching of constant phase shifters
Low accuracy
Process variation dependency
Part to part variation
Difficult to calibrate each phase shifter

23. Phased Array Antennas Main Disadvantages
Low resolution (beam steering jumps by a few degrees)
Typically switching of constant phase shifters
Low accuracy
Process variation dependency
Part to part variation
Difficult to calibrate each phase shifter
Non linear frequency response

24. Phased Array Antennas Main Disadvantages
Low resolution (beam steering jumps by a few degrees)
Typically switching of constant phase shifters
Low accuracy
Process variation dependency
Part to part variation
Difficult to calibrate each phase shifter
Non linear frequency response
Silicon size is typically inversely proportional to the frequency
Lower frequency phase shifters are big

25. Phased Array Antennas Main Disadvantages
Low resolution (beam steering jumps by a few degrees)
Typically switching of constant phase shifters
Low accuracy
Process variation dependency
Part to part variation
Difficult to calibrate each phase shifter
Non linear frequency response
Silicon size is typically inversely proportional to the frequency
Lower frequency phase shifters are big
Difficult to build large antennas
Constant delay RF routing
Long routing with several RF splitting / additions
Not true time delay (explained later)

26. Phased Array Antennas Main Disadvantages
Low resolution (beam steering jumps by a few degrees)
Typically switching of constant phase shifters
Low accuracy
Process variation dependency
Part to part variation
Difficult to calibrate each phase shifter
Non linear frequency response
Silicon size is typically inversely proportional to the frequency
Lower frequency phase shifters are big
Difficult to build large antennas
Constant delay RF routing
Long routing with several RF splitting / additions
Not true time delay (explained later)
Difficult to build multibeam antennas
Requires RF summation and splitting
Number of beams in a RF chip needs to be known in advance

27. Phased Array Antennas Main Disadvantages
Low resolution (beam steering jumps by a few degrees)
Typically switching of constant phase shifters
Low accuracy
Process variation dependency
Part to part variation
Difficult to calibrate each phase shifter
Non linear frequency response
Silicon size is typically inversely proportional to the frequency
Lower frequency phase shifters are big
Difficult to build large antennas
Constant delay RF routing
Long routing with several RF splitting / additions
Not true time delay (explained later)
Difficult to build multibeam antennas
Requires RF summation and splitting
Number of beams in a RF chip needs to be known in advance
Can not support large bandwidth
Not true time delay (explained later)

28. Phased Array Antennas Main Disadvantages
Low resolution (beam steering jumps by a few degrees)
Typically switching of constant phase shifters
Low accuracy
Process variation dependency
Part to part variation
Difficult to calibrate each phase shifter
Non linear frequency response
Silicon size is typically inversely proportional to the frequency
Lower frequency phase shifters are big
Difficult to build large antennas
Constant delay RF routing
Long routing with several RF splitting / additions
Not true time delay (explained later)
Difficult to build multibeam antennas
Requires RF summation and splitting
Number of beams in a RF chip needs to be known in advance
Can not support large bandwidth
Not true time delay (explained later)
Difficult to support large scanning angles

29. Maximum Bandwidth for 3dB Loss Vs. Scan Angle
Array Size

30. Phased Array Frequency Response
16x16 elements, square, Spacing d = /2, Steering 45o, 45o
Center frequency = 30GHz, Bandwidth = 2 GHz
Perfect Equalizer:
SNR Loss = dB
Beam Edge Loss = 2.46 dB

31. Phased Array Frequency Response
64 elements, linear, Spacing d = /2, Steering 45o off-boresight
Center frequency = 30GHz, Bandwidth = 2 GHz
Boresight
Perfect Equalizer:
SNR Loss = dB
Beam Edge Loss = 9.81 dB

32. Types of Electrically Steered Antennas
Phased shifter based Antennas
Metamaterial Antennas
True Time Delay (TTD) Antennas
Established technology
Many companies building chips: ADI, Aw
Easy to build, easy to show initial results
Reasonable power consumption
Reasonable cost (depends on chips)
WILL BE DOMINATED BY CHINESE
Innovative, Silicon based proven technology
High resolution, perfect accuracy
High scalability – size & bandwidth
Inherent multibeam support
Low cost
limited antenna array size
Limited bandwidth
Beam squint
Difficult to support multibeam, many instances
Challenging Calibration Process
“Exotic” technology
Low efficinecy
No multibeam capabilities
Tracking speed
Temperature handling
Requires expensive NRE based silicon chips
Higher power by nature (ADC and DAC per element). Improved with silicon process node
NULLING

33. ESMA Technology Size vs. Bandwidth
Inherent benefits of DIGITAL
Unlimited number of antenna elements, allowing large panels at high BW
True Time Delay
(TTD)
Phased Array technology bandwidth limit

34. Calibration
Need to calibrate every element in phase and amplitude to get the gain of the array
Among other topics
Frequency
Temperature
Delay
Scanning angles
VCO
Aging
Most sophisticated and difficult part of the process. Relatively easy to operate an array at boresite, but not easy at all to do over all parameters
Huge advantage of DIGITAL Beam Forming

35. End to End System Its not just about the antenna
In an Aero antenna there are 5 parts
Antenna
BUC/LNB
ACU Modem
Power Supply
ESMA supports all in a single antenna board: Power in – Ethernet out
Having integral modem is significant advantage
ACU (very important in multi-beam)
Low Power modes: No data – no power
Integrated with Hub side

36. Summary I: Phased Array Antenna Vs. TTD
Many people sell chips for analog phase shifters
Easy to build single beam antennas with limited performance and limited scan angles
Market is expected to be dominated by low cost Chinese products in 5 years
It is when you try to calibrate when you start encountering difficulties
Phased array antennas have many limitations:
Beam Squint
Array size
Bandwidth
Scan angle
TTD solves all this issues: Requires dedicated silicon chips but provide superior performance

37. Summary II: Best Payload Technology
16 X 500MHz beams
Full Duplex Tx, Rx arrays with X,000 elements, with tapering
Link with 6db SNR for 10 db G/T User Terminal
Full digital beam forming
SDR Modem with Beam Hopping and On-Board-Processing
Less than 1 KW
All enabled on True Time Delay Beam-Forming

38. Summary III Electronic Vs Mechanical Solutions - Comparison
Mechanical/other terminals
ESMA
Terminal structure
Multiple components: Antennas, HPA, LNA, Modem
Single (all-in-one) aperture
No. of beams 1
Multibeam/multi-polarization
Moving parts
Yes
None
Make-before-break X √
Beam switching time
Long
< 100 microseconds
Move customers to LEO/MEO
Future proof
Software define antenna with inherent SDR Modem
Terminal Profile and weight
High
< 5 cm, low weight

39. Thank You
SatixFy