Nā ʻano o nā Microwaves
ʻO nā microwaves kekahi ʻāpana o ka electromagnetic spectrum i hoʻohana nui ʻia i ke ola hou, mai nā kamaʻilio uea ʻole a hiki i nā lako hale. ʻOiai e pili pinepine ʻia me nā umu microwave, he kuleana nui ko nā microwaves, ʻoi aku hoʻi i ka ʻenehana radar, nā satelite, nā pūnaewele kelepona, a me nā ʻōnaehana hoʻokele. I mea e maopopo ai ke kumu he mea nui nā microwaves, pono mākou e hoʻomaopopo i ko lākou mau ʻano nui: ka laulā alapine a me ka nalu, nā ʻano hoʻolaha, nā pilina me nā mea, nā waiwai noʻonoʻo a me ke komo ʻana, a me nā mea palekana i kā lākou hoʻohana ʻana.
1. Ke kūlana o nā microwaves i loko o ka electromagnetic spectrum
He mau nalu electromagnetic nā microwave, ʻo ia hoʻi, hiki iā lākou ke hoʻolaha me ka ʻole o kahi medium (vacuum) a loaʻa iā lākou nā kahua uila a me nā kahua magnetic oscillating e kū pono ana kekahi i kekahi. Ma keʻano laulā, ʻokoʻa ka alapine (frequency) o nā microwave mai kahi o 300 MHz a i 300 GHz, me nā nalu mai kahi o 1 mika a i 1 millimeter. Hoʻonoho kēia pae iā lākou ma waena o nā nalu lekiō (nā alapine haʻahaʻa) a me ka infrared (nā alapine kiʻekiʻe).
Ma muli o ka pōkole o ko lākou mau nalu i hoʻohālikelike ʻia me nā nalu lekiō haʻahaʻa, hiki i nā microwave ke lawe i ka nui o ka ʻike a ʻae i ka hoʻohana ʻana i nā antennas liʻiliʻi. ʻO kēia kekahi kumu he kumu nui nā microwaves o nā ʻōnaehana kamaʻilio hou.
2. Ka wikiwiki o ka hoʻolaha ʻana a me nā waiwai kumu
E like me nā nalu electromagnetic ʻē aʻe, hele nā microwaves i ka wikiwiki o ka mālamalama i loko o kahi vacuum, ʻo ia hoʻi ma kahi o 3 × 10⁸ m/s. I loko o kahi medium e like me ka ea, plastic, a i ʻole nā ʻiʻo olaola, lohi iki ka wikiwiki ma muli o ka refractive index o ka medium.
Loaʻa i nā microwave nā ʻano maʻamau o nā nalu, e like me:
– ʻAkaʻaka: hiki ke ʻakaʻaka ʻia e nā ʻili metala a i ʻole nā mea alakaʻi.
– Refraction: loli ke kuhikuhi o ka hoʻolaha ʻana ke komo ia i loko o kahi medium me nā waiwai uila like ʻole.
– Diffraction (kūlou): hiki ke kūlou ma mua o ka lihi o kahi pale, akā ʻoi aku ka liʻiliʻi o ka pae o ka diffraction ma mua o nā nalu lekiō nona ka nalu lōʻihi.
– Ke komohewa ʻana: hiki i nā microwave ʻelua ke hoʻoikaika a hoʻonāwaliwali paha kekahi i kekahi ma muli o ke ʻano.
Hoʻohana nui ʻia kēia mau waiwai i ka radar a me nā kamaʻilio kelepona, akā hiki ke hana i nā pilikia e like me ka multipath (nā noʻonoʻo pālua) i nā ʻōnaehana Wi-Fi a i ʻole nā kamaʻilio kelepona.
3. ʻO ke kuhikuhi o ka hoʻolaha ʻana he "laina ʻike"
ʻO kekahi ʻano koʻikoʻi o nā microwaves ʻo ia ko lākou ʻano e hoʻolaha ma kahi laina pololei (laina-o-ka-ʻike), ʻoi aku hoʻi ma nā alapine kiʻekiʻe. Ma muli o ko lākou mau nalu pōkole, ʻaʻole kūlou maʻalahi nā microwaves me nā ʻaoʻao o ka Honua e like me nā nalu lekiō haʻahaʻa. ʻO ka hopena, pono pinepine nā kamaʻilio microwave mamao loa:
- nā antennas ma nā hale kiaʻi kiʻekiʻe,
- mea hoʻihoʻi hou a i ʻole ka relay,
– a i ʻole ka ukali ma ke ʻano he mea hoʻohui.
ʻO kēia ke kumu e hoʻohana pinepine ʻia ai nā pūnaewele loulou microwave ma waena o nā hale kiaʻi e hoʻohui i ʻelua mau wahi e hiki ke "ʻike" kekahi i kekahi me ka ʻole o ke ālai ʻia e nā hale a me nā puʻu.
4. Ka launa pū ʻana me nā mea: ka omo ʻana a me ka hoʻomehana dielectric
ʻO ke ʻano kaulana loa o nā microwaves ʻo ia ko lākou hiki ke hoʻomehana i kekahi mau mea, ʻoiai nā mea i loaʻa nā molekala polar e like me ka wai. Hana ʻia kēia kaʻina hana hoʻomehana ma o ka hoʻomehana dielectric: ke kumu o ke kahua uila o ka microwave i nā molekala polar (e.g., H₂O) e wili a oscillate, a laila e hoʻololi ana i ka ikehu nalu i ikehu wela.
Eia nō naʻe, he mea nui e hoʻomaopopo ʻaʻole like ke ʻano o ka wela ʻana o nā mea a pau. Pili nā ʻano hoʻomehana i:
- ka nui o ka wai,
- ke kūpaʻa dielectric,
- kumu pohō dielectric,
- ka mānoanoa o nā mea a me ka hoʻolaha ʻana o ke kahua.
Hoʻopili ka metala i nā microwaves, no laila ʻaʻole ia e wela maʻalahi (ke ʻole ka hana ʻia ʻana o kahi hunaahi e kahi mea ʻoi). ʻOi aku ka maʻalahi o ke aniani a me kekahi mau plastik i nā microwaves, no laila ʻaʻole e wela koke kā lākou mau ipu e like me ka meaʻai—ʻoiai hiki nō iā lākou ke mahana mai ka hoʻopā ʻana me ka meaʻai wela.
5. Nā hiki ke komo i kaupalena ʻia akā pono
Loaʻa i nā microwave ka hiki ke komo i loko o kekahi mau mea ʻaʻole alakaʻi, akā ua kaupalena ʻia ko lākou hohonu komo ʻana a hilinaʻi ʻia i ke alapine (frequency) a me nā ʻano o ka mea. I loko o nā umu microwave o ka hale, ʻo ke alapine (frequency) maʻamau i hoʻohana ʻia he 2,45 GHz. Ua koho ʻia kēia alapine (frequency) ma ke ʻano he ʻaelike: ua lawa ka pono e hoʻomehana i ka meaʻai a ua lawa ka hohonu komo ʻana no nā ʻāpana meaʻai o kēlā me kēia lā.
Ma nā noi ʻē aʻe, hoʻohana ʻia nā microwaves i:
- radar aniau e ʻike i nā kulu ua a me nā ʻano ʻino,
- ke kiʻi microwave no ka nānā ʻana i nā mea,
– nā kamaʻilio ukali e hoʻohana ana i nā alapine (pinepine) kikoʻī (e.g. C-band, Ku-band, Ka-band).
6. ʻO ka polarization a me kona mana ma nā ʻōnaehana kamaʻilio
Loaʻa i nā microwaves ka polarization, ʻo ia ke kuhikuhi o ke kahua uila i kona hoʻolaha ʻana. Hiki i ka polarization ke linear (horizontal/vertical), circular, a i ʻole elliptical. I ke kamaʻilio ʻana, he mea nui ka hoʻohālikelike polarization ma waena o ka transmitter a me ka mea loaʻa no ka mea hiki i kahi mismatch ke hōʻemi i ka mana hōʻailona i loaʻa.
Hoʻohana ʻia ka polarization i:
- ho'ēmi i ka hoʻopilikia ʻana,
- ka hoʻonui ʻana i ka mana o ke kahawai (e.g. me ka dual-polarization),
- hoʻololi i nā kūlana hoʻolaha kikoʻī, ʻoi aku hoʻi i nā kamaʻilio ukali.
7. Nā mana o ka lewa: ka damping a me ka ua
I loko o nā microwaves, hiki i ka lewa ke loaʻa kahi hopena koʻikoʻi, ʻoiai ma nā alapine kiʻekiʻe. ʻO kekahi mau hanana koʻikoʻi:
– Ka mae ʻana o ka ua: omo nā kulu ua a hoʻopuehu i nā nalu, ʻoiai ma nā alapine Ku a me Ka, no laila hiki ke emi ka maikaʻi o nā hōʻailona ukali a i ʻole nā loulou microwave i ka wā ua nui.
– Ka omo ʻana e ka mahu wai a me ka oxygen: ma kekahi mau alapine (frequency) aia kahi piko omo, no laila aia kahi "puka makani alapine" i ʻoi aku ka maikaʻi no ke kamaʻilio ʻana ma kahi mamao loa.
– Ka hoʻopuehu ʻana: hiki i nā ʻāpana i ka lewa ke hana i ka hoʻopuehu ʻana e hoʻopilikia ai i ke kūpaʻa o ka hōʻailona.
No laila, pono e noʻonoʻo nā mea hoʻolālā ʻōnaehana microwave i ka palena mana, ke koho ʻana o ke kaula alapine (frequency band), a me nā ʻano hana modulation a me ka hoʻoponopono hewa.
8. ʻO ka noʻonoʻo ikaika e ka metala a me ke kumumanaʻo hana o ka radar
Hoʻākāka nui ʻia nā hawewe microwave e nā mea alakaʻi e like me ka metala. ʻO kēia ʻano ke kumu o ka ʻenehana radar (Radio Detection and Ranging). Hoʻopuka ka radar i nā hawewe microwave a laila loaʻa i nā nalu i hoʻākāka ʻia e helu i ka mamao, ka wikiwiki, a me ke kuhikuhi o kahi mea. No ka mea he pōkole nā hawewe microwave, hiki i ka radar ke ʻike i nā kikoʻī maikaʻi aʻe ma mua o nā ʻōnaehana me nā nalu lōʻihi.
Hoʻohana ʻia ka radar ma nā ʻano hana:
- ka hoʻokele ʻana i nā mokulele a me nā moku,
- radar kaʻa (e.g. no ka hoʻokele holo adaptive),
- ka nānā ʻana i ke aniau,
– ka palapala ʻāina ʻili honua (ʻike mamao).
9. Nā palena palekana a me ka hōʻike ʻana
He radiation non-ionizing nā microwaves, ʻo ia hoʻi, ʻaʻole lawa ko lākou ikehu e uhaki i nā pilina kemika e like me nā kukuna X. ʻO ka pilikia nui mai ka ʻike ʻana i ka microwave e pili ana i ka hoʻomehana ʻana o nā ʻiʻo ma nā ikaika kiʻekiʻe. No laila, hoʻokumu nā kūlana palekana i nā palena hōʻike no ka lehulehu a me nā limahana, a ua hoʻolālā ʻia nā mea hana e mālama i nā hoʻokuʻu ʻana i loko o nā palena palekana.
Ma nā mea hana e like me nā umu microwave, ua hoʻolālā ʻia nā pale hao a me nā grille ma ka puka e mālama i nā microwave i loko o ke keʻena hoʻomehana. Hoʻopuka nā mea kamaʻilio e like me Wi-Fi a me nā kelepona paʻalima i ka mana haʻahaʻa ma mua o nā umu microwave, no laila aia ka ʻike ʻana i loko o nā palena kānāwai.
10. Manaʻo
ʻO nā ʻano o ka microwave e komo pū me kahi alapine kiʻekiʻe me nā nalu pōkole, kahi ʻano no ka hoʻolaha ʻana o ka laina, ka noʻonoʻo ikaika e nā metala, a me kahi pilina ʻano me nā mea dielectric e hiki ke hoʻomehana. Hoʻopilikia pū ʻia nā microwave e nā kūlana lewa, ʻoiai ka ua a me ka omo ʻana o ke kinoea, a hoʻokomo i ka manaʻo o ka polarization, he mea nui ia i ke kamaʻilio ʻana. ʻO ka hoʻomaopopo ʻana i kēia mau ʻano e hiki ai iā mākou ke ʻike i ke kumu he mea nui loa nā microwave i ke ola hou: hiki iā lākou ke kamaʻilio wikiwiki, nā ʻōnaehana radar pololei, a me nā ʻenehana hoʻomehana kūpono—inā hoʻohana ʻia me nā kūlana hoʻolālā kūpono a me ka palekana.
