Bandwidth yog lwm qhov tseem ceeb ntawm antenna. Bandwidth piav qhia txog ntau yam zaus uas lub antenna tuaj yeem xa lossis txais lub zog kom raug. Feem ntau, bandwidth xav tau yog ib qho ntawm cov kev ntsuas siv los xaiv hom antenna. Piv txwv li, muaj ntau hom antennas nrog bandwidths me me heev. Cov antennas no siv tsis tau rau hauv cov ntawv thov broadband.
Feem ntau bandwidth yog hais txog voltage sawv nthwv dej piv (VSWR). Piv txwv li, lub antenna yuav piav qhia tias muaj VSWR <1.5 dhau 100-400 MHz. Cov lus hais tias tus coefficient reflection tsawg dua 0.2 hla qhov zaus hais. Yog li ntawd, ntawm lub zog xa mus rau lub antenna, tsuas yog 4% ntawm lub zog rov qab mus rau lub transmitter. Tsis tas li ntawd, rov qab poob S11 = 20 * LOG10 (0.2) = 13.98 decibels.
Thov nco ntsoov tias qhov saum toj no tsis tau txhais hais tias 96% ntawm lub zog raug xa mus rau lub antenna hauv daim ntawv ntawm cov hluav taws xob electromagnetic propagated. Yuav tsum xav txog qhov poob zog.
Tsis tas li ntawd xwb, tus qauv hluav taws xob yuav hloov pauv raws li zaus. Feem ntau, cov duab ntawm tus qauv hluav taws xob tsis hloov pauv qhov zaus.
Kuj tseem yuav muaj lwm cov qauv siv los piav qhia txog bandwidth. Qhov no tuaj yeem ua polarizing hauv qee qhov ntau thiab tsawg. Piv txwv li, lub antenna circularly polarized tuaj yeem piav qhia tias muaj qhov sib piv axial ntawm <3 dB los ntawm 1.4-1.6 GHz (tsawg dua 3 dB). Qhov ntau thiab tsawg polarization bandwidth teeb tsa no yog kwv yees li rau cov antennas circularly polarized.
Bandwidth feem ntau yog teev nyob rau hauv nws Fractional Bandwidth (FBW). FBW yog qhov sib piv ntawm qhov zaus faib los ntawm qhov zaus nruab nrab (zaus siab tshaj plaws rho tawm qhov zaus qis tshaj plaws). Tus "Q" ntawm lub antenna kuj cuam tshuam txog bandwidth (Q siab dua txhais tau tias bandwidth qis dua thiab vice versa).
Yuav muab qee cov piv txwv ntawm bandwidth, ntawm no yog cov lus qhia ntawm bandwidths rau cov hom antenna feem ntau. Qhov no yuav teb cov lus nug, "bandwidth ntawm dipole antenna yog dab tsi?" thiab "Lub antenna twg muaj bandwidth siab dua - patch lossis helix antenna?". Piv txwv li, peb muaj antennas nrog lub zaus nruab nrab ntawm 1 GHz (gigahertz) txhua.
Bandwidths ntawm ntau lub antennas.
Raws li koj tuaj yeem pom los ntawm lub rooj, qhov bandwidth ntawm lub antenna tuaj yeem sib txawv heev. Patch (microstrip) antennas yog bandwidth qis heev, thaum helical antennas muaj bandwidth loj heev.
Lub sijhawm tshaj tawm: Kaum Ib Hlis-24-2023
