*4.2.2 Deployable large antennas for tiny satellites*

For some specific operations electrically large antennas can be needed on CubeSats. Those antennas are folded, stowed or packed in a CubeSat before and during launch process. After satellite platform is placed into orbit they are deployed to conduct their missions. For this aim, there are deployable antenna examples where cutting edge mechanical technologies are employed (**Figure 17**).

A stowed 0.5 m Ka-band mesh reflector antenna was installed into RaInCube platform to initiate usage of Ka-Band radar for meteorology on a low-cost and fast

#### **Figure 17.**

*Ka-band deployable parabolic dish antenna which has 30 ribs similar to an umbrella to be stowed and installed into RaInCube platform. Left deployed and right stowed into RaInCube (image courtesy of NASA/ JPL-Caltech).*

#### **Figure 18.**

*Measured and calculated radiation pattern of the deployable mesh reflector antenna model. (a)* ϕ *= 0°. (b)*  ϕ *= 90°. (Reprinted, with permission, from [25], © 2016 IEEE).*

applicable 6 U CubeSat platform of NASA [23–25]. The measured gain and efficiency of this antenna are 42.6 dBi and 52%, respectively, at 35.75 GHz [23].

Radiation pattern of the reflector antenna is given in **Figure 18**. Its beamwidth is about 1.2° in E- and H-planes. RaInCube was launched into a near circular orbit where its altitude of ~400 km and with inclination of 51.6° on 21 May 2018 and the mesh reflector antenna deployment process achieved on 28 July 2018.

#### *4.2.3 GEO satellite communication antennas*

In the past, GEO satellites' main mission was only television broadcasting and voice data transmission. Therefore, there are many communication satellites as geosynchronous. In the last decade, they have started evolving and internet communication mission has begun to take place instead of TV broadcasting. The main reason for this is that the internet goes into all areas of life like business, education, entertainment, etc.

Since GEO satellites are about 36,000 km away from earth, they need high effective isotropic radiated power (EIRP) levels. So usually large aperture reflector antennas are employed. Based on ITU regulations generally these antennas shape their beams according to geographical regions. This is because to reuse frequencies allocated over regions as shown in **Figure 3**.

There are many different applications of reflector antennas for GEO communication satellites [26–33].

There is a good example to illustrate evolutionary change of GEO communication satellites. To provide high speed internet data communication JAXA started The "KIZUNA" – Wideband InterNetworking engineering test and Demonstration Satellite (WINDS) project. Its main mission was to enable super high-speed data communications of up to 1.2 Gbps. In this way, everybody can reach high-speed communications, no matter in which geographical region of Japan they live. Its illustration and its payload antennas are shown in **Figure 19**.

As shown in **Figure 19** there are three payload antenna structures on the satellite. Two of them are Ka-Band multibeam reflector antennas and the other one is Ka-Band Active Electronically-Controlled Scanning Array (AESA) antenna. The multibeam antennas have 2.4 m diameter and in type of 2 offset-feed Cassegrain. The AESA has 128 elements to establish transmit and receive beams. Multibeam reflector antennas are responsible for Japan with Asia and AESA is operational for Pacific and partly Asia.

KIZUNA was launched and put into Geosynchronous Orbit to acquire the highest-speed data communication of the world in 2008. Its planned operational life was 5 years and failed in February 2019 and started to drift. Therefore, it exceeded its planned operational life successfully.

#### *4.2.4 Reflector antennas*

A big number of scientist and communication antenna specialists are working on the increase of performance properties of reflector antennas for the widely usage in deep space communication, satellite communication stations, radio astronomy, current microwaves such as radio-links and radars. Parabolic reflector antennas are preferred to use as main reflector in communication systems due to its high gain and directivity properties. Also, these types of reflector antennas can give the opportunity for usage in multi-band and multi beam applications. For these reasons parabolic reflector antennas have attracted the intense interest of researchers for many years [34, 35]. A simple and known physical structure of a parabolic reflector antenna is in **Figure 20**.

**157**

carefully analyzed and designed.

links on the same path) form

satellite-downlink paths) form

receiver paths) form

*Antennas for Space Applications: A Review DOI: http://dx.doi.org/10.5772/intechopen.93116*

**Figure 19.**

**Figure 20.**

*courtesy of NASA).*

A parabolic reflector antenna consists of many important sections such as main reflector, feed, struts and control units, pedestal or support. Each of these should be

*Parabolic reflector antennas at The NASA Deep Space Network Goldstone Ground Station Complex (image* 

• Receiver-transformer operation (single earth antenna at the end of down-up

• Transmitter and receiver (two different earth antennas at the ends of uplink-

• Transmitter, satellite control unit and receiver (three different earth antennas at the ends of uplink-satellite-control unit paths and control units–satellite-

• A number of earth reflector antennas depending on coverage areas of satellites.

Additionally, it is possible to use reflector antennas in various forms as:

*KIZUNA" – WINDS high speed data communication satellite (image courtesy of JAXA).*

#### **Figure 19.**

*Advanced Radio Frequency Antennas for Modern Communication and Medical Systems*

mesh reflector antenna deployment process achieved on 28 July 2018.

*4.2.3 GEO satellite communication antennas*

allocated over regions as shown in **Figure 3**.

illustration and its payload antennas are shown in **Figure 19**.

entertainment, etc.

cation satellites [26–33].

Pacific and partly Asia.

*4.2.4 Reflector antennas*

antenna is in **Figure 20**.

its planned operational life successfully.

applicable 6 U CubeSat platform of NASA [23–25]. The measured gain and efficiency of this antenna are 42.6 dBi and 52%, respectively, at 35.75 GHz [23].

Radiation pattern of the reflector antenna is given in **Figure 18**. Its beamwidth is about 1.2° in E- and H-planes. RaInCube was launched into a near circular orbit where its altitude of ~400 km and with inclination of 51.6° on 21 May 2018 and the

In the past, GEO satellites' main mission was only television broadcasting and voice data transmission. Therefore, there are many communication satellites as geosynchronous. In the last decade, they have started evolving and internet communication mission has begun to take place instead of TV broadcasting. The main reason for this is that the internet goes into all areas of life like business, education,

Since GEO satellites are about 36,000 km away from earth, they need high effective isotropic radiated power (EIRP) levels. So usually large aperture reflector antennas are employed. Based on ITU regulations generally these antennas shape their beams according to geographical regions. This is because to reuse frequencies

There are many different applications of reflector antennas for GEO communi-

There is a good example to illustrate evolutionary change of GEO communication satellites. To provide high speed internet data communication JAXA started The "KIZUNA" – Wideband InterNetworking engineering test and Demonstration Satellite (WINDS) project. Its main mission was to enable super high-speed data communications of up to 1.2 Gbps. In this way, everybody can reach high-speed communications, no matter in which geographical region of Japan they live. Its

As shown in **Figure 19** there are three payload antenna structures on the satellite. Two of them are Ka-Band multibeam reflector antennas and the other one is Ka-Band Active Electronically-Controlled Scanning Array (AESA) antenna. The multibeam antennas have 2.4 m diameter and in type of 2 offset-feed Cassegrain. The AESA has 128 elements to establish transmit and receive beams. Multibeam reflector antennas are responsible for Japan with Asia and AESA is operational for

KIZUNA was launched and put into Geosynchronous Orbit to acquire the highest-speed data communication of the world in 2008. Its planned operational life was 5 years and failed in February 2019 and started to drift. Therefore, it exceeded

A big number of scientist and communication antenna specialists are working on the increase of performance properties of reflector antennas for the widely usage in deep space communication, satellite communication stations, radio astronomy, current microwaves such as radio-links and radars. Parabolic reflector antennas are preferred to use as main reflector in communication systems due to its high gain and directivity properties. Also, these types of reflector antennas can give the opportunity for usage in multi-band and multi beam applications. For these reasons parabolic reflector antennas have attracted the intense interest of researchers for many years [34, 35]. A simple and known physical structure of a parabolic reflector

**156**

*KIZUNA" – WINDS high speed data communication satellite (image courtesy of JAXA).*

#### **Figure 20.**

*Parabolic reflector antennas at The NASA Deep Space Network Goldstone Ground Station Complex (image courtesy of NASA).*

A parabolic reflector antenna consists of many important sections such as main reflector, feed, struts and control units, pedestal or support. Each of these should be carefully analyzed and designed.

Additionally, it is possible to use reflector antennas in various forms as:


#### *Advanced Radio Frequency Antennas for Modern Communication and Medical Systems*

Parabolic reflector can be fed as in axisymmetric, asymmetric and off-focus fed forms as seen in **Figure 21**. Symmetric feeding causes aperture blockage effects of feed and struts. To avoid this blockage, asymmetric and off-focus fed forms are preferred. For multiple beam generation array type feedings have been used. The approximate maximum gain of a parabolic reflector is given as below:

$$\mathbf{G}\_{\text{max}} = \frac{4\pi A\_{\text{eff}}}{\mathcal{A}^2} \tag{4}$$

Here, *A*eff is effective aperture area including the effect of losses due to spillover, aperture taper, Joule type heating and distortions on the surface of reflector.

Reflector antennas have different shapes such as parabolic, hyperbolic, elliptic, circular and line profiles. Although the shapes are quite different, for mathematical analysis they can be converted to each other by defining a parameter called eccentricity. Using eccentricity parameter, the whole family can be analyzed in a unified form [36]. Various shapes and their eccentricity values are illustrated in **Figure 22**.

Incident and reflected field directions for a feed located at the focus of parabolic and hyperbolic antennas are seen in **Figure 23**.

In order to increase gains of parabolic reflector antennas, dual antenna structures can be used. Cassegrain (main reflector parabolic antenna and sub-reflector hyperbolic reflector) and Gregorian (main reflector parabolic antenna and subreflector ellipsoid reflector) are two most common types of dual antennas. As an example, a Cassegrain type reflector antenna is presented in **Figure 24**.

A dual-antenna can be fed in symmetrical, asymmetrical and off-focus forms as given in **Figure 25**.

There are several methods for the analysis of reflector antennas. Physical optics (PO) comes first among the known methods [37]. As it is known, it gives the correct results for the main lobe and first side lobe patterns [38].

PO integral has main difficulty in application due to the complexity of the physical structure. The diffraction effects are also considered in order to obtain the full and correct radiation patterns particularly to determine side and back lobes. Physical theory of diffraction (PTD), equivalent edge currents (EEC) [39], aperture field method (AFM) and Jacobi-Bessel series method have been applied to find the radiation patterns for front space of reflector antenna [40]. The uniform theory of diffraction (UTD) [41–43]

**Figure 21.** *Feeding types of a parabolic reflector antenna, (a) symmetric, (b) asymmetric, and (c) off-focus fed.*

**159**

**Figure 24.**

*diameter is 70 m (image courtesy of NASA).*

and the uniform asymptotic theory (UAT) [44] based on the geometrical theory of diffraction (GTD) [45, 46] can be used in the analysis of radiation patterns of reflector antennas for various directions. These methods applied to the analysis of reflector

*DSS-43 dish at the Canberra Deep Space Communication Complex (CDSCC): a Cassegrain antenna whose* 

*Incident and reflected field directions of a reflector antenna (a) parabolic and (b) hyperbolic.*

antennas by many researchers [44, 47, 48] as seen in **Figure 26**.

*Antennas for Space Applications: A Review DOI: http://dx.doi.org/10.5772/intechopen.93116*

*Variation of reflector shapes with eccentricity.*

**Figure 22.**

**Figure 23.**

*Antennas for Space Applications: A Review DOI: http://dx.doi.org/10.5772/intechopen.93116*

**Figure 22.**

*Advanced Radio Frequency Antennas for Modern Communication and Medical Systems*

approximate maximum gain of a parabolic reflector is given as below:

Parabolic reflector can be fed as in axisymmetric, asymmetric and off-focus fed forms as seen in **Figure 21**. Symmetric feeding causes aperture blockage effects of feed and struts. To avoid this blockage, asymmetric and off-focus fed forms are preferred. For multiple beam generation array type feedings have been used. The

> max 2 <sup>4</sup> *Aeff <sup>G</sup>* p

aperture taper, Joule type heating and distortions on the surface of reflector.

and hyperbolic antennas are seen in **Figure 23**.

given in **Figure 25**.

l

Here, *A*eff is effective aperture area including the effect of losses due to spillover,

Reflector antennas have different shapes such as parabolic, hyperbolic, elliptic, circular and line profiles. Although the shapes are quite different, for mathematical analysis they can be converted to each other by defining a parameter called eccentricity. Using eccentricity parameter, the whole family can be analyzed in a unified form [36]. Various shapes and their eccentricity values are illustrated in **Figure 22**. Incident and reflected field directions for a feed located at the focus of parabolic

In order to increase gains of parabolic reflector antennas, dual antenna structures can be used. Cassegrain (main reflector parabolic antenna and sub-reflector hyperbolic reflector) and Gregorian (main reflector parabolic antenna and subreflector ellipsoid reflector) are two most common types of dual antennas. As an

A dual-antenna can be fed in symmetrical, asymmetrical and off-focus forms as

There are several methods for the analysis of reflector antennas. Physical optics (PO) comes first among the known methods [37]. As it is known, it gives the correct

PO integral has main difficulty in application due to the complexity of the physical structure. The diffraction effects are also considered in order to obtain the full and correct radiation patterns particularly to determine side and back lobes. Physical theory of diffraction (PTD), equivalent edge currents (EEC) [39], aperture field method (AFM) and Jacobi-Bessel series method have been applied to find the radiation patterns for front space of reflector antenna [40]. The uniform theory of diffraction (UTD) [41–43]

*Feeding types of a parabolic reflector antenna, (a) symmetric, (b) asymmetric, and (c) off-focus fed.*

example, a Cassegrain type reflector antenna is presented in **Figure 24**.

results for the main lobe and first side lobe patterns [38].

<sup>=</sup> (4)

**158**

**Figure 21.**

*Variation of reflector shapes with eccentricity.*

**Figure 23.** *Incident and reflected field directions of a reflector antenna (a) parabolic and (b) hyperbolic.*

#### **Figure 24.**

*DSS-43 dish at the Canberra Deep Space Communication Complex (CDSCC): a Cassegrain antenna whose diameter is 70 m (image courtesy of NASA).*

and the uniform asymptotic theory (UAT) [44] based on the geometrical theory of diffraction (GTD) [45, 46] can be used in the analysis of radiation patterns of reflector antennas for various directions. These methods applied to the analysis of reflector antennas by many researchers [44, 47, 48] as seen in **Figure 26**.

**Figure 25.** *Feeding types of dual antennas, (a) symmetrical, (b) asymmetrical, and (c) off-focus.*

**Figure 26.**

*Radiation pattern of a parabolic reflector antenna, D = 15*λ*,,* α *= π/3, for focus fed [39] and off-focus fed with fx = fy = fz =* λ*. [40].*

The use of array type feeding has been preferred for easy beam scanning in single and dual-reflectors by some scientists [29]. Also in recent years, some new techniques have been developed in the analysis of off-focus fed and array feeding in single and dual reflectors for preventing aperture blockage of feeds, struts and subreflectors. These techniques are called as equivalent feed [49, 50] and equivalent parabola techniques [51]. By using the combination of these two techniques, it is possible to minimize side and back lobes [52, 53] (**Figure 27**).

As well known, it is important to reduce fields due to such lobes. Additional advantages of these techniques are optimization of the location of off-focus feeders and array elements. Thus beam scanning and corrections for catching the best receive/transmit signal are achieved. All these give the ability of increasing the performance of the space communication systems from the aspects of reflector antenna systems.

#### **4.3 Antennas for deep space vehicles**

For exploring other planets, comets, moons etc., space vehicles carrying scientific instrumentation are designed and launched. To compensate overmuch free

**161**

**Figure 28.**

*Antennas for Space Applications: A Review DOI: http://dx.doi.org/10.5772/intechopen.93116*

operate in harsh space environment.

between Mars and Earth at X-band.

ent elevation angles.

**Figure 29**.

**Figure 27.**

space loss in communication budget, high gain antennas are needed. Therefore, challenging design and manufacturing technologies are employed for those antennas. Moreover, they have to comply with hard space qualification standards to

*n = 8 and fx = fy = fz = 3*λ *by using equivalent feed and equivalent paraboloid techniques [40, 53].*

*Radiation pattern of a defocused fed Cassegrain antenna with D = 100*λ*, do = 90*λ*, F = 62.5*λ*,* β *= 150, e = 1.996,* 

High gain antenna (HGA) on Mars rover **Curiosity** *of Mars Science Laboratory (MSL)* can be given as a pertinent example. HGA was developed by EADS CASA Espacio for NASA/JPL-Caltech [54]. This is circularly polarized microstrip patch array antenna consisting of 48 elements on a gimbal system to send and receive data

In **Figure 28**, Engineering Qualification Model (EQM) of HGA is seen. The gimbal system has two degree of freedom for pointing. This RHCP antenna's gain values for Rx and Tx frequencies are listed in **Tables 3** and **4**, respectively, at differ-

This antenna is still being used on *Curiosity* at X-Band for uplink and downlink

data from Mars surface to Earth. Its image taken by itself on Mars is shown in

*EQM of HGA used for MSL (image taken from [54]; ©EurAAP; used with permission).*

#### **Figure 27.**

*Advanced Radio Frequency Antennas for Modern Communication and Medical Systems*

*Feeding types of dual antennas, (a) symmetrical, (b) asymmetrical, and (c) off-focus.*

The use of array type feeding has been preferred for easy beam scanning in single and dual-reflectors by some scientists [29]. Also in recent years, some new techniques have been developed in the analysis of off-focus fed and array feeding in single and dual reflectors for preventing aperture blockage of feeds, struts and subreflectors. These techniques are called as equivalent feed [49, 50] and equivalent parabola techniques [51]. By using the combination of these two techniques, it is

*Radiation pattern of a parabolic reflector antenna, D = 15*λ*,,* α *= π/3, for focus fed [39] and off-focus fed with* 

As well known, it is important to reduce fields due to such lobes. Additional advantages of these techniques are optimization of the location of off-focus feeders and array elements. Thus beam scanning and corrections for catching the best receive/transmit signal are achieved. All these give the ability of increasing the performance of the space communication systems from the aspects of reflector

For exploring other planets, comets, moons etc., space vehicles carrying scientific instrumentation are designed and launched. To compensate overmuch free

possible to minimize side and back lobes [52, 53] (**Figure 27**).

**160**

antenna systems.

**Figure 26.**

**Figure 25.**

*fx = fy = fz =* λ*. [40].*

**4.3 Antennas for deep space vehicles**

*Radiation pattern of a defocused fed Cassegrain antenna with D = 100*λ*, do = 90*λ*, F = 62.5*λ*,* β *= 150, e = 1.996, n = 8 and fx = fy = fz = 3*λ *by using equivalent feed and equivalent paraboloid techniques [40, 53].*

space loss in communication budget, high gain antennas are needed. Therefore, challenging design and manufacturing technologies are employed for those antennas. Moreover, they have to comply with hard space qualification standards to operate in harsh space environment.

High gain antenna (HGA) on Mars rover **Curiosity** *of Mars Science Laboratory (MSL)* can be given as a pertinent example. HGA was developed by EADS CASA Espacio for NASA/JPL-Caltech [54]. This is circularly polarized microstrip patch array antenna consisting of 48 elements on a gimbal system to send and receive data between Mars and Earth at X-band.

In **Figure 28**, Engineering Qualification Model (EQM) of HGA is seen. The gimbal system has two degree of freedom for pointing. This RHCP antenna's gain values for Rx and Tx frequencies are listed in **Tables 3** and **4**, respectively, at different elevation angles.

This antenna is still being used on *Curiosity* at X-Band for uplink and downlink data from Mars surface to Earth. Its image taken by itself on Mars is shown in **Figure 29**.


**Table 3.**

*Rx gain values of HGA [54].*


#### **Table 4.**

*Tx gain values of HGA [54].*

**Figure 29.** *HGA shown on Curiosity Mars rover (image courtesy of NASA/JPL-Caltech).*

MSL was launched on 26 November 2011 and landed on 5 August 2012 onto Mars surface successfully. It was still working while this book chapter was being written.

Another challenging antenna design and application for deep space mission is *Mars Cube One* (MarCO) project of NASA/JPL-Caltech. NASA launched a Mars lander whose name is *Interior Exploration using Seismic Investigations, Geodesy and Heat Transport* (InSight) to Mars on 5 May 2018. There were two accompanying CubeSats: MarCO-A and MarCO-B to relay data to Earth from InSight on Mars [55]. As shown in **Figure 30** there is a deployable X-Band reflectarray antenna on the back surface of solar arrays.

The main task of this antenna with X-Band transponder is to support the communication of NASA's Mars Reconnaissance Orbiter (MRO) for downlink of the telemetries during InSight Rover's entry, descent and landing phases. This reflectarray antenna has 29.2dBic gain at X-Band as mentioned in [55].

**163**

are shown.

**Figure 31.**

**Figure 30.**

*Antennas for Space Applications: A Review DOI: http://dx.doi.org/10.5772/intechopen.93116*

*Front view of MarCO CubeSat (image courtesy of NASA/JPL-Caltech).*

An impressive image was taken by onboard camera with fisheye lens of MarCO-B after reflectarray antenna and its feed were deployed as given in **Figure 31**. In this figure, reflectarray elements and microstrip patch array feed of it are seen obviously. MarCO sent related telemetries from InSight successfully until its contact with the

*Deployed reflectarray antenna with Mars scene. This photo was taken by onboard camera with fisheye lens of* 

Since reflectarray antennas have low stowage volume, manufacturing easiness using printed circuit board technology and lightweight mass, they became

antenna to be used on LEO satellites [56]. Through this project many reflectarray prototypes in different element arrangements were designed, manufactured and measured. In **Figures 32** and **33**, simulation and measurement of the reflectarray antenna where the elements have been arranged in rectangular form at X-Band

started a project named as YADAS in 2015 to develop X-Band reflectarray

<sup>2</sup> TUBITAK: The Scientific and Technological Research Council of Turkey.

Space Technologies Research Institute

ground station was lost in February 2019.

*MarCO-B (image courtesy of NASA/JPL-Caltech).*

attractive in space industry. TUBITAK<sup>2</sup>

### *Antennas for Space Applications: A Review DOI: http://dx.doi.org/10.5772/intechopen.93116*

#### **Figure 30.**

*Advanced Radio Frequency Antennas for Modern Communication and Medical Systems*

**Required gain (dBi)**

7145 MHz 21.4 18 18.9 16

**Measured gain (dBi)**

**Measured gain (dBi)**

MSL was launched on 26 November 2011 and landed on 5 August 2012 onto Mars surface successfully. It was still working while this book chapter was being written. Another challenging antenna design and application for deep space mission is *Mars Cube One* (MarCO) project of NASA/JPL-Caltech. NASA launched a Mars lander whose name is *Interior Exploration using Seismic Investigations, Geodesy and Heat Transport* (InSight) to Mars on 5 May 2018. There were two accompanying CubeSats: MarCO-A and MarCO-B to relay data to Earth from InSight on Mars [55]. As shown in **Figure 30** there is a deployable X-Band reflectarray antenna on the

**At** ϴ **= 2° At** ϴ **= 3.8°**

**At** ϴ **= 2° At** ϴ **= 5°**

**Measured gain (dBi)**

**Measured gain (dBi)**

> **Required gain (dBi)**

**Required gain (dBi)**

**Required gain (dBi)**

8390 MHz 22.9 21.5 20.7 19.5

8420 MHz 22.9 21.1 8455 MHz 22.7 20.7

7170 MHz 21.5 18.8 7195 MHz 21.5 18.8

The main task of this antenna with X-Band transponder is to support the communication of NASA's Mars Reconnaissance Orbiter (MRO) for downlink of the telemetries during InSight Rover's entry, descent and landing phases. This reflectar-

ray antenna has 29.2dBic gain at X-Band as mentioned in [55].

*HGA shown on Curiosity Mars rover (image courtesy of NASA/JPL-Caltech).*

**162**

**Table 4.**

**Figure 29.**

**Table 3.**

*Tx gain values of HGA [54].*

*Rx gain values of HGA [54].*

back surface of solar arrays.

*Front view of MarCO CubeSat (image courtesy of NASA/JPL-Caltech).*

#### **Figure 31.**

*Deployed reflectarray antenna with Mars scene. This photo was taken by onboard camera with fisheye lens of MarCO-B (image courtesy of NASA/JPL-Caltech).*

An impressive image was taken by onboard camera with fisheye lens of MarCO-B after reflectarray antenna and its feed were deployed as given in **Figure 31**. In this figure, reflectarray elements and microstrip patch array feed of it are seen obviously. MarCO sent related telemetries from InSight successfully until its contact with the ground station was lost in February 2019.

Since reflectarray antennas have low stowage volume, manufacturing easiness using printed circuit board technology and lightweight mass, they became attractive in space industry. TUBITAK<sup>2</sup> Space Technologies Research Institute started a project named as YADAS in 2015 to develop X-Band reflectarray antenna to be used on LEO satellites [56]. Through this project many reflectarray prototypes in different element arrangements were designed, manufactured and measured. In **Figures 32** and **33**, simulation and measurement of the reflectarray antenna where the elements have been arranged in rectangular form at X-Band are shown.

<sup>2</sup> TUBITAK: The Scientific and Technological Research Council of Turkey.

#### **Figure 32.**

*Simulated and measured reflectarrays within YADAS project at X-band [56] (image courtesy of TUBITAK Space Technologies Research Institute).*

#### **Figure 33.**

*Directivity comparison of simulation and measurement result for reflectarray antenna where the elements have been arranged in rectangular form (YADAS) [56] (image courtesy of TUBITAK Space Technologies Research Institute).*

The developed antennas reached Technology Readiness Level (TRL) 4. Some studies are going on to bring beam-shaping capabilities to the designed reflectarrays.

#### **5. Conclusions**

Since Sputnik-1 was launched into orbit, the space technologies and antennas for spacecraft and satellite communications have been making progress rapidly. Thanks to this progress humankind have been learning about planets, comets, stars and moons, briefly near, deep and even interstellar space. Moreover, exploiting this technology, people can communicate with each other easily even if they are not in same country or continent. This is also an important cause of globalization.

**165**

*Antennas for Space Applications: A Review DOI: http://dx.doi.org/10.5772/intechopen.93116*

**Acknowledgements**

**Abbreviations**

AFM aperture field method ASS amateur satellite service

BSS broadcasting satellite service

EES Earth exploration satellite service

EIRP effective isotropic radiated power EQM engineering qualification model

GNSS global navigation satellite system

EEC equivalent edge currents

ESA European Space Agency

FSS fixed satellite service

GEO geostationary orbit

bps bit per second

In this chapter, antennas have been discussed as an RF-front end element of communication subsystems on spacecrafts and satellites. As can be seen from subsections of the chapter, there are many different antenna types used to provide communication services of space vehicles. Because of the limited space and for the sake of brevity only remarkable ones have been given as examples. An interested reader can find many other antenna examples used for space applications in open literature. Design parameters and their types are generally defined according to their frequency bands, transmit RF power, mass and volume requirements, mission type and environmental conditions. Therefore, like other equipment and subsystems to be used on the mission, they should be tested based on the published standards. Many of parts of these standards have been created from past mission experiences, experiments and trials. Two well-known space agencies, NASA and ESA have been publishing detailed standard documents and they are continuously updating them based on the "lessons learned" and experimental improvements. Today countries are trying to enhance budget and qualified man power devoted

to the space all over the world. Because they know that by this means they can develop many different technologies in fields of aerospace, defense, and mobile communication. Nevertheless, space industry is a long-term investment and it needs passion, sustainability, and also patience, because in this technological area the final product emerges after many detailed research and development stages.

The authors would like to express special thanks to TUBITAK Space Technologies Research Institute (TUBITAK UZAY), National Aeronautics and Space Administration (NASA), Japan Aerospace Exploration Agency (JAXA), The Institute of Electrical and Electronics Engineers (IEEE) and the European Association on Antennas and Propagation (EurAAP) for permissions of some specific photographs and figures to use in this chapter. The authors also thank to Dr.

Aslı ER AKAN for editing and redrawing figures within the text.

AESA active electronically-controlled scanning array

CDSCC Canberra Deep Space Communication Complex

ECSS The European Cooperation for Space Standardization

ESTEC European Space Research and Technology Centre EurAAP European Association on Antennas and Propagation

GEVS general environmental verification standard

#### *Antennas for Space Applications: A Review DOI: http://dx.doi.org/10.5772/intechopen.93116*

*Advanced Radio Frequency Antennas for Modern Communication and Medical Systems*

*Simulated and measured reflectarrays within YADAS project at X-band [56] (image courtesy of TUBITAK* 

The developed antennas reached Technology Readiness Level (TRL) 4. Some studies are going on to bring beam-shaping capabilities to the designed

*Directivity comparison of simulation and measurement result for reflectarray antenna where the elements have been arranged in rectangular form (YADAS) [56] (image courtesy of TUBITAK Space Technologies Research* 

Since Sputnik-1 was launched into orbit, the space technologies and antennas for spacecraft and satellite communications have been making progress rapidly. Thanks to this progress humankind have been learning about planets, comets, stars and moons, briefly near, deep and even interstellar space. Moreover, exploiting this technology, people can communicate with each other easily even if they are not in same country or continent. This is also an important cause of globalization.

**164**

reflectarrays.

**Figure 33.**

*Institute).*

**Figure 32.**

*Space Technologies Research Institute).*

**5. Conclusions**

In this chapter, antennas have been discussed as an RF-front end element of communication subsystems on spacecrafts and satellites. As can be seen from subsections of the chapter, there are many different antenna types used to provide communication services of space vehicles. Because of the limited space and for the sake of brevity only remarkable ones have been given as examples. An interested reader can find many other antenna examples used for space applications in open literature. Design parameters and their types are generally defined according to their frequency bands, transmit RF power, mass and volume requirements, mission type and environmental conditions. Therefore, like other equipment and subsystems to be used on the mission, they should be tested based on the published standards. Many of parts of these standards have been created from past mission experiences, experiments and trials. Two well-known space agencies, NASA and ESA have been publishing detailed standard documents and they are continuously updating them based on the "lessons learned" and experimental improvements.

Today countries are trying to enhance budget and qualified man power devoted to the space all over the world. Because they know that by this means they can develop many different technologies in fields of aerospace, defense, and mobile communication. Nevertheless, space industry is a long-term investment and it needs passion, sustainability, and also patience, because in this technological area the final product emerges after many detailed research and development stages.
