Polarization ndechimwe chezvinhu zvakakosha zveantennas. Isu chekutanga tinoda kunzwisisa polarization yemafungu endege. Isu tinogona kukurukura mhando huru dzeantenna polarization.
linear polarization
Isu tichatanga kunzwisisa polarization yeplane electromagnetic wave.
A planar electromagnetic (EM) wave ine akati wandei maitiro. Chekutanga ndechekuti simba rinofamba munzira imwe (hapana ndima inoshanduka mune maviri orthogonal nzira). Chechipiri, simba remagetsi uye magnetic field perpendicular kune mumwe nemumwe uye orthogonal kune mumwe nemumwe. Magetsi uye magineti minda inotenderera kune kutungamira kwendege wave kuparadzira. Semuenzaniso, funga imwe-frequency electric field (E field) inopiwa ne equation (1). Iyo electromagnetic munda iri kufamba munzira +z. Munda wemagetsi unotungamirirwa mu +x direction. Iyo magnetic field iri munzira +y.
Mukuenzanisa (1), cherechedza chinyorwa: . Iyi iyuniti vector (vector yehurefu), iyo inotaura kuti electric field point iri mu x direction. Iyo ndege inobhururuka inoratidzwa muMufananidzo 1.
mufananidzo 1. Graphical inomiririra yendima yemagetsi inofamba munzira +z.
Polarization ndiyo yekutsvaga uye kuparadzira chimiro (contour) yemunda wemagetsi. Semuenzaniso, funga nezve ndege wave electric field equation (1). Tichacherechedza nzvimbo iyo munda wemagetsi uri (X,Y,Z) = (0,0,0) sekushanda kwenguva. Iyo amplitude yemunda uyu yakarongwa muMufananidzo 2, pane akati wandei nenguva. Munda uri kutenderera pa frequency "F".
mufananidzo 2. Cherekedza nzvimbo yemagetsi (X, Y, Z) = (0,0,0) panguva dzakasiyana.
Munda wemagetsi unocherechedzwa pamabviro, uchifamba uchidzokera kumashure neamplitude. Munda wemagetsi unogara uchitevedza yakaratidzwa x-axis. Sezvo munda wemagetsi uchichengetwa uchitevedza mutsara mumwe chete, munda uyu unogona kunzi uri mutsetse polarized. Pamusoro pezvo, kana X-axis ichienderana nepasi, iyi ndima inotsanangurwa zvakare seyakatwasuka polarized. Kana munda wacho wakanangana neiyo Y-axis, iyo wave inogona kunzi yakasimudzwa polarized.
Linearly polarized mafungu haadi kutungamirwa neakisi yakachinjika kana yakatwasuka. Semuyenzaniso, electric field wave ine chinomanikidzira chakarara pamutsara sezvakaratidzwa muFigure 3 inozovewo mutsara polarized.
mufananidzo 3. Iyo yemagetsi munda amplitude ye linearly polarized wave iyo trajectory ikona.
Munda wemagetsi muMufananidzo 3 unogona kutsanangurwa nekuenzanisa (2). Ikozvino kune x uye y chikamu chemunda wemagetsi. Zvose zvikamu zvakaenzana muhukuru.
Chinhu chimwe chekucherechedza nezve equation (2) ndiyo xy-chikamu uye minda yemagetsi padanho rechipiri. Izvi zvinoreva kuti zvikamu zvese zvine maamplitude akafanana nguva dzese.
circular polarization
Iye zvino fungidzira kuti nzvimbo yemagetsi yewaivha yendege inopiwa ne equation (3):
Muchiitiko ichi, X- uye Y-elements i90 madhigirii kunze kwechikamu. Kana munda uchicherechedzwa se (X, Y, Z) = (0,0,0) zvakare sepakutanga, tambo yemagetsi maringe nenguva ichaonekwa sezvakaratidzwa pasi apa mumufananidzo 4.
Mufananidzo 4. Simba remagetsi emagetsi (X, Y, Z) = (0,0,0) EQ domain. (3).
Munda wemagetsi muMufananidzo 4 unotenderera mudenderedzwa. Iyi mhando yemunda inotsanangurwa se circularly polarized wave. Kune circular polarization, zvinotevera zvinofanirwa kuzadzikiswa:
- Standard for circular polarization
- Munda wemagetsi unofanirwa kuva nezvikamu zviviri zve orthogonal (perpendicular).
- Izvo zvikamu zve orthogonal zvemunda wemagetsi zvinofanirwa kunge zvine amplitudes yakaenzana.
- Izvo zvikamu zve quadrature zvinofanira kunge zviri 90 degrees kunze kwechikamu.
Kana uchifamba paWave Figure 4 skrini, kutenderera kwemunda kunonzi kunopesana newachi uye kurudyi-ruoko rwakatenderedzwa polarized (RHCP). Kana munda ukatenderedzwa munzira yewachi, munda unenge uri kuruboshwe-ruboshwe denderedzwa polarization (LHCP).
Elliptical polarization
Kana nzvimbo yemagetsi ine zvikamu zviviri zveperpendicular, 90 madhigirii kunze kwechikamu asi chehukuru hwakaenzana, munda uchava elliptically polarized. Tichifunga nezvemunda wemagetsi wendege wave kufamba ichienda +z, inotsanangurwa neEquation (4):
Nzvimbo yenzvimbo iyo iyo muromo wemagetsi munda wevector ichatora inopiwa muMufananidzo 5.
Mufananidzo 5. Kurumidza elliptical polarization wave electric field. (4).
Munda uri muFigure 5, uchifamba wakanangana newachi, ungave werudyi-ruboshwe kana uchifamba kunze kwescreen. Kana iyo electric field vector ichitenderera yakatarisana, munda uchange uri kuruboshwe-elliptically polarized.
Uyezve, elliptical polarization inoreva eccentricity yayo. Reshiyo ye eccentricity kune amplitude yemahombe nemadiki axes. Semuenzaniso, iyo wave eccentricity kubva kuequation (4) ndeye 1/0.3 = 3.33. Elliptically polarized waves inotsanangurwa zvakare nekutungamira kweiyo axis hombe. Iyo wave equation (4) ine axis inonyanya kuumbwa ne x-axis. Ziva kuti axis hombe inogona kunge iri chero kona yendege. Iko kona haidiwi kuti ikwane X, Y kana Z axis. Chekupedzisira, zvakakosha kuziva kuti ese ari maviri denderedzwa uye mutsara polarization zviitiko zvakakosha zveelliptical polarization. 1.0 eccentric elliptically polarized wave is a circularly polarized wave. Elliptically polarized waves ane eccentricity isingaperi. Linearly polarized waves.
Antenna polarization
Izvozvi zvatave kuziva nezve polarized plane wave electromagnetic fields, iyo polarization yeantenna inotsanangurwa.
Antenna Polarization Antenna kure-munda ongororo, iyo polarization yeinokonzeresa radiated munda. Naizvozvo, antennas anowanzo kunyorwa se "linearly polarized" kana "kurudyi-ruoko rwerudyi denderedzwa polarized antennas".
Iyi pfungwa yakapusa yakakosha kune antenna kutaurirana. Chekutanga, antenna yakatwasuka polarized haitaure neiyo vertically polarized antenna. Nekuda kweiyo reciprocity theorem, antenna inotamisa uye inogamuchira nenzira imwecheteyo. Naizvozvo, vertically polarized antennas anofambisa uye anogashira vertically polarized minda. Naizvozvo, kana iwe ukayedza kuburitsa vertically polarized horizontally polarized antenna, hapazove nekugamuchirwa.
Muchiitiko chakawanda, kune maviri ane mutsara polarized antenna akatenderedzwa kune imwe neimwe nekona ( ), kurasikirwa kwesimba nekuda kweiyi polarization mismatch ichatsanangurwa neiyo polarization kurasikirwa factor (PLF):
Naizvozvo, kana maantenna maviri aine polarization yakafanana, kona iri pakati penzvimbo dzawo dzemaerekitironi anopenya i zero uye hapana kurasikirwa kwemagetsi nekuda kwekukanganiswa kwepolarization. Kana imwe antenna yakasimudzwa yakatwasuka uye imwe yacho yakatwasuka polarized, kona yacho i90 madhigirii, uye hapana simba richatamiswa.
CHERECHEDZA: Kufambisa foni pamusoro pemusoro wako kumakona akasiyana kunotsanangura kuti sei kugamuchira kunogona kuwedzera dzimwe nguva. Nharembozha antennas dzinowanzoita mutsara polarized, saka kutenderedza foni kunowanzo kuenderana nepolarization yefoni, nekudaro kunatsiridza kugamuchirwa.
Circular polarization chimiro chinodiwa cheantenna mazhinji. Ose maantenna akatenderedzwa polarized uye haatambudzi nekurasikirwa kwechiratidzo nekuda kwekukanganiswa kwepolarization. Antennas anoshandiswa muGPS masisitimu ane ruoko rwerudyi rwakatenderedzwa polarized.
Zvino fungidzira kuti mutsara polarized antenna inogamuchira denderedzwa polarized masaisai. Saizvozvo, fungidzira kuti denderedzwa polarized antenna inoedza kugashira mutsara polarized masaisai. Chii chinokonzera polarization kurasikirwa chinhu?
Rangarira kuti denderedzwa polarization chaizvoizvo maviri orthogonal linearly polarized masaisai, 90 madhigirii kunze kwechikamu. Naizvozvo, iyo linearly polarized (LP) antenna inongogashira iyo denderedzwa polarized (CP) wave chikamu chikamu. Naizvozvo, iyo LP antenna ichave nepolarization mismatch kurasikirwa kwe0.5 (-3dB). Ichi ichokwadi zvisinei kuti ndeipi kona iyo antenna yeLP inotenderedzwa. saka:
Polarization kurasikirwa chinhu dzimwe nguva inonzi polarization kunyatsoita, antenna mismatch factor, kana antenna yekugamuchira chinhu. Mazita ose aya anoreva pfungwa imwe chete.
Nguva yekutumira: Zvita-22-2023
