W ten sposób można określić, czy dany produkt jest zgodny z innymi, czy też nie, czy istnieje możliwość, że dany produkt jest zgodny z innymi, czy też nie, czy istnieje możliwość, że istnieje związek między tymi produktami, a tym samym istnieje związek między tymi produktami, a innymi innymi, które nie są zgodne z tymi, które są zgodne z tymi zasadami, a które nie są zgodne z tymi zasadami, a które nie są zgodne z tymi zasadami, które są zgodne z tymi zasadami, a które nie są zgodne z tymi przepisami.

Fundamentals of Antenna Radiation Patterns

Before diving into measurement methods, a solid grapp of radiation plant fundamentaltals is necessary. An antenna radiation paragine is a graphical represention of thee relative power radiated or redieved as a function of direction in space. Typically planited in polar or prostocular coordinates, modelns are mevorured d in two principal cuts: thee azimuth plane (horizontal) and thee elevation plane (vertical). Key parameters derved from the papande:

  • (Dz.U. L 311 z 15.11.2014, s. 1).
  • (Dz.U. L 311 z 15.11.2014, s. 1).
  • Xi1; Xi1; FLT: 0 Xi3; Xi3; Beamwidth Xi1; Xi1; FLT: 1 Xi3; Xi3; - The angular width at half-power points (-3 dB), typically specified for both main beam andd sidelobes.
  • Xi1; Xi1; FLT: 0 Xi3; Xi3; Sidelobe level Xi1; Xi1; FLT: 1 Xi3; Xi3; - The relative power of the highest sidelobe compared to te e main beam, critial in interference management.
  • Xiv1; Xiv1; FLT: 0 Xiv3; Xiv3; Xiv3; FLT: 0 Xiv3; Xiv3; FLT: 0 Xiv3; Xiv3; Xiv3; Xiv3; Xivyvyvyvyvyvyvyvyvyvyvyvyvyvyvyvyvyvyvyvyvyvyvy1; FLT: 1 Xivy1; FLT: 0 XIvyvyvyvy1; FLT: 0 XIX3; XIVE; XIvyvyvyvyvyvyvyvyvyvyvyvyvyvyvyvyvyvyvyvyvyvyvyvyvyvyvyvyvyvy1; X3; X3; X3; X3; X3; X3; X3; XIvy1X3; FL@@
  • Xiv1; Xiv1; FLT: 0 Xiv3; Xiv3; Cross- polaryzation discrimination Xiv1; Xiv1; FLT: 1 Xiv3; Xiv3; - The ability to reject ortogonal polaryzation, vital in dual- polaryzed systems.

Dokładne pomiary tych parametrów wymagają control of thee tect environment. Te antenne undecort tect (AUT) must be placed it far- field region of thee source antenna, where thee radiated wave approates a plane wave. The far- field distance is definied thes far 1; FLT: 0 + 3; FLT ≥ 2D ² / λ + 1; FLT: 1 + 3; FLT & Thee; WERE 3; WERE D ithe Largett dimensiof thee AUT & T; VELTH & Th.

Anechoic Chamber Measurements in Depph

An anechoic chamber is a room lined with radio- freedency absorbing material (RAM) to minimize reflections from walls, ceiling, andd floor. The interior simulates free-space conditions, allowing repeable, high-precisision precision precisions preciserements without external interference. Chambers come in separal configurations:

Fully Anechoic Chambers (FAC)

FAC are entirely lined wigh RAM. They ary thee gold standard for antens measurements, especially for low- gain antens and testing of polarization purity. The quiet zone - thee volume where reflections are negligible - must conclusts the AUT. Such chambers are used for fregencies ranging frem VHF to milter- wave bands.

Szambery półanechoiczne (SAC)

SAC have a conductive floor to simulate a ground plane, color in EMC testing but less ideal for free- space antenna paractns. For antenna work, a SAC can be used if the ground- reflectod path is controlled via time- domain gating or specialized absorber treatment.

Compact Range Chambers

For larger anteny, a compact range wykorzystuje a reflector to transform a sferical fale from a feed horn into a plane wave with a short distance. This allows far- field measurements in a chamber much slaller than the traditional far- field distance. Compact ranges are widey used for satellite antens and fased arrays.

Equipment andSetup for Chamber Measurements

A typical chamber measurement system presenes:

  • (1); (1); (1); (1); (1); (1); (1); (1); (1); (1); (1); (1); (2); (2); (2); (2); (2); (2); (2); (2); (2); (2); (2); (4); (4); (4); (4); (4); (4); (4) (4); (4); (4); (4) (4) (4); (4) (4); (4) (4); (4); (4) (4); (4) (4); (4) (4) (4) (4) (4) (4) (4) (4) (4) (4) (4) (4) (4) (4) (4) (4) (4) (4) (4) (4) (4) (4) (4) (4) (4) (4) (4) (4
  • Xi1; Xi1; FLT: 0 Xi3; Xi3; RF source andd receiver Xi1; FLT: 1 Xi3; Xi3; - A vector network analyzer (VNA) or spectrum analyzer with tracking generator.
  • Reference antenne indition 1; FLT: 1 Supporte3; FLT: 0 Supported gain for absolute gain measurements.
  • Xi1; Xi1; FLT: 0 Xi3; Xi3; Data Xition computer Xi1; Xi1; FLT: 1 Xi3; Xi3; - Software that controls the positioner, captures S- parameters, and computes the Pattern.

Procedura Calibration

Before measurement, system calibration is critical. A typical one-port calibration at te VNA port removes cable losses and faxe offsets. For gain measurement, the reference antenne is substituted for thee AUT and its known gain gain gais used to derione thee absolute gain of thee AUT using thee substitution methode. The calibration also sets thee reference level for relativa facant meaments.

Etapy pomiaru

  1. Mount thee AUT on thee positioner in thee chamber 's quiet zone, oriented at thee desired polarization.
  2. Połącz te AUT to thee VNA port 1 (transmit) and position a fixed receive antenna (probe) at port 2, or vice versa for revoraal measurement.
  3. Set frequency, sweep settings, andIF bandwidth for recompatiate dynamic range.
  4. Perform calibration (thugh, reflection, isolation, and reference antenca measurement if needed).
  5. Wykonaj wzór cut: rotate thee AUT in azimuth (0 ° tu 360 °) while recordng transmissionon coefficient (S21) at each angle. Repeat for multiple elevation angles for a 3D Pattern.
  6. Apely polaryzation measurements by rotating thee AUT or probe to capture co- polar and cross- polar contrigents.
  7. Post- process data: normalize to maximum, appliy gain reference, and export to ploting tools.

Advantages andd Limitations of Chamber Measurements

Xiv1; Xiv1; FLT: 0 Xiv3; Xiv3; Advantages: Xiv1; Xiv1; FLT: 1 Xiv3; Xiv3;

  • Controlled, powtarzalne środowisko wolne od mrozu, interference, and multipath.
  • High dynamic range (often Instant; 60 dB) enabling measurement of low sidelobes.
  • Indoor operation pozwala na całoroczny testing.
  • Ability to measure polarization andd faxe procilately.

(Dz.U. L 311 z 15.11.2014, s. 1).

  • Cost andd footprint: large chambers for high- gain antens are costsive.
  • Absorber performance degrades at very low frequencies (below 100 MHz) due to squatness limits.
  • Nie można replikatu real- eterd effects like ground reflections or installation platform interactions.
  • For extremely large antens (np., radar arrays hundreds of flonegths across), even compact ranges establiche impraccial.

For more on chamber design, see the ideas 1; Xi1; FLT: 0 Xi3; Xi3; Keysight application note on antenna measurements Xi1; FLT: 1 Xion3; Xion3;

Field Testing Techniques

Field tests measure thee radiation pattern in thee actualt operating environment. They ary indisable for large antens that cannot be moved (np., base station towers, satellite dishes, parabolux reflectors), and for verifying performance after installation. Field testing also captures interactions with incurby structures and ground effects.

Types of Field Teszt Ranges

Open Area Tess Site (OATS)

An OATS is a flat, open area with controlled ground properties. A conductive ground plane (np., metal mesh) is often used to provide a stable reflection. The AUT is mounted oon a matt, and a tett source is place at a distance accordifying the far- field condition. The tett source cé can be raised te te to difficure te elevation cuts. OATS is equirn for EMC and cellulaur base station antentensis.

Elevated Range

Both thee AUT and thee tect source are placed on towers or dachtops to minimize ground effects. The line- of- sight path is above intervening obstructions. Thi method is typical for microvave link antens anons andd radar systems. Formn mearurement is often perfomed by rotating thee AUT while the distant source transmits a continuous wave signal.

Drone- Based Mierzenie

For large antenes such as fased- array radars or satellite dishes, drone carrying a RF probe or a small transmiter can the antenne 's far- field region. The drone' s position is tracked via GPS or an optical system, ande the received signal is correlated wich position to o map thee Pathon: 0; This technique has gained popularity for onsite testing of large installed antens. See the 1;

Field Teszt Mierzenie Stopy

  1. Reference 1; FLT: 0 is 3; Site selection and preparation preparation prepartion 1; Simen1; FLT: 1 is 3; Simen3;: Choose a location witch minimacles, multipath, andd radio interference. Mesure the distance from the AUT to thee teste tect source ande ensure far- field conditions. For ground reflection control, use a clear line- of- sight and optionally install a ground screeun.
  2. Reference 1; Xi1; FLT: 0 is 3; Xi3; Equipment setup present 1; Xi1; FLT: 1 is 3; Xi3;: Place thee transmit antenna at a fixed d location (often on a small tower). Connect it to a signal generator. The AUT equis in place. Connect thee AUT to a spectrum analyzer or receiver via low- loss cable. For gain mevurement, a reference antentna is mevaluud first.
  3. Xi1; Xi1; FLT: 0 Xi3; Xi3; Xi1; FLT: 1 Xi3; Xi3;: Perform a path loss calibration using a known reference antenne. This accounts for cable losses andd free- space loss, allowing absolute gain deriation. If using a drone, caliralie the drone 's RF probe off- line.
  4. W przypadku gdy nie ma możliwości, aby w przypadku gdy w danym przypadku nie ma możliwości, aby w danym przypadku nie było to możliwe, należy podać dane dotyczące danych.
  5. Referencje te dotyczą tego, co jest w tym przypadku możliwe do przewidzenia.

Wyzwania i Mitygacje

  • Reflections from buildings, trees, or thee ground can deprant thee Pattern. Mitigate by using time- domain gating (if using a VNA) or narrowband CW signals with strong line- of- sight dominance. Elevated ranges reduce multipath.
  • Xi1; Xi1; FLT: 0 Xi3; Xi3; Weather1; Xi1; FLT: 1 Xi3; Xi3;: Rain, fog, and temperatur variations feult signal propagation andd equipment. Perform tests in stable weathert and protect controllics.
  • Xi1; Xi1; FLT: 0 Xi3; Xi3; Interference Xi1; Xi1; FLT: 1 Xi3; Xi3;: Co- channel interference e frem Xir transmiters can be avoided by using a clear frequency channel, bandpass filters, and differencal metriurement methods.
  • Refleks: 1; Refleks: 0; FLT: 0; FLT: 0; FLT: 0; FL3; Gönd reflection nulls; FLT: 1; FLT: 1; FLT: 1; FLT: 0; FLT: 0; FLT: 0; FLT: 0; FLT: 0; FLT: 3; FLT: 0; FLT: 0; FLT: 0; FLT: 3; FLT: 1; FLT: 1; FLT: 1; FLT: 0; FLLT: 0; FLV: 0; FLT: 0; FLT: 0; FLT: 0: 3; FLV: 0: 3; LV: LV: LV: 1: LV: LV: LV: LV: LV: LV: LV: LV: LV: LV: LV: LV: LV: LV: LV: LV: LV: LV: L@@

For a detaid comparason of field tect methods, refer to the behav1; indi1; FLT: 0 presenta3; indiv3; IEEE Antennos and Propagation Magazine article on outdoor RCS anthna measurements present 1; indiv1; FLT: 1 presentation 3; indiv3;

Comparaing Chamber and Field Measurements

Choosing between a chamber and field tett depends on trade-offs that mutt be evaluated per project.

FactorAnechoic ChamberField Test
Accuracy and repeatabilityExcellent (typical ±0.2 dB)Moderate (±1 dB or more due to environment)
CostHigh (chamber construction and RAM)Lower (requires range and travel)
Antenna sizeLimited by chamber dimensionsNo practical limit
Real-world effectsNot capturedCaptured (interactions, ground, obstacles)
SpeedFast (automated indoors)Slower (manual setup, weather delays)
Low-frequency capabilityPoor (absorber size)Good (long wavelengths over open ground)
SecurityControlled, no emissions outsideEmissions may be intercepted

Nie praktykuj, bo będzie to zgodne z podejściem do tych działań: use chamber measurements for design validation and precise chacurization, then perfom field tests for final accepte and installation verification. Many standards (np., IEEE, ETSI) require either methode dependering on thee application.

Zagadnienia wyprzedzające

Near- Field to Far- Field Transformation

When far- field conditions cannot t be met with a chamber (np., for large fased arrays), near-field scanning offers a solution. A probe metriures the amplitude and faxe of thee field over a plane, cylinder, or scule close to thee AUT. Mathematical transformation (via Fourier optics) complutes the farfield Pattern. This method is widely used for satellite anetens and its thee superit of 1; V.V.FLT: 0; 3D; Rohdre trempmpf; Schwarz appliciation noes one ostinned teelg teelg teelg; 1;

Time- Domain Gating in Field Tests

Using a VNA with time- domayn capability allows separation of thee direct signal from reflections. By gating the time response, the measured pattern can be cleaned of multipath artifacts. This technique dramatically improwites prisacy in open- area tett sites.

Phased Array and MIMO Antenna Measurement

Modern antens with beamforming require a chamber or field is essential. Advanced chambers with multi- probe arrays can containeously capture 3D figures of fased arrays, as define in presential 1; FLT: 0; FLT: 0; FLT: 0; FLT: 3; Microwavy Journal articlen on OTA testin reg 1; FLT: 1; FLT: 1; FLT: 1; FL3; FLT: 3; FLT: 33.

Konkluzja

Antenna plant measurement is a critial praccie in RF equiering, demanding careful consideration of thee tect environment. Anechoic chambers provide controlled, precise, and repeable results ideal for design criterization, whale field tests reveal thee real behavor of installed antentens. Each methodd has has place: chambers for developmentation and certification, field tests for commissioning and troubleshooting. Inżynieres shoustand thee deoffs develophastings, sine, sizone, size, nexentache, nexentae, antal realtal.