With the development of communication technology, handheld radio papa kaapuni pinepine Hoʻohana nui ʻia ka ʻenehana, e like me: pager uea ʻole, kelepona paʻalima, PDA uea ʻole, a pēlā aku. ʻO kekahi o nā hiʻohiʻona nui loa o kēia huahana lawe lima ʻo ia ka miniaturization, a ʻo ka miniaturization ʻo ia hoʻi ke kiʻekiʻe loa o nā ʻāpana, kahi e hoʻopilikia ai nā mea (me SMD, SMC, chip hanau, a pēlā aku.) Inā ʻaʻole lawelawe lima pono ʻia nā hōʻailona hoʻoweliweli electromagnetic, ʻaʻole holo pono paha ka ʻōnaehana puni holoʻokoʻa. No laila, pehea e pale ai a kāohi ai i ka hoʻopili electromagnetic a hoʻomaikaʻi i ka pilina electromagnetic i lilo i kumuhana nui i ka hoʻolālā ʻana o ka RF circuit PCB. ʻO ke kaapuni hoʻokahi, ʻokoʻa ka hoʻolālā hoʻolālā PCB, ʻokoʻa ʻokoʻa kāna papa kuhikuhi hana. Kūkākūkā kēia pepa pehea e hoʻonui ai i ka hana o ke kaapuni e loaʻa ai nā pono hoʻokae uila i ka hoʻohana ʻana i ka polokalamu Protel99 SE e hoʻolālā i ka PCB kaapuni PC o nā huahana pāma.

1. Koho o ka pā

The substrate of printed circuit board includes organic and inorganic categories. ʻO nā waiwai nui o ka substrate ka dielectric mau ε R, ka mea dissipation (a i ʻole ka make dielectric) ʻo Tan δ, coefficient CET a me ka hoʻonui ʻana o ka wai i ka wai. ε R affects circuit impedance and signal transmission rate. No nā kaapuni alapine kiʻekiʻe, ʻo ka ʻae ʻana o ka ʻae ka mea mua a ʻoi aku ka koʻikoʻi e noʻonoʻo ai, a ʻo ke substrate me ka haʻahaʻa haʻahaʻa haʻahaʻa e koho.

2. PCB design process

Because Protel99 SE software is different from Protel 98 and other software, the process of PCB design by Protel99 SE software is briefly discussed.

① Because Protel99 SE adopts the PROJECT database mode management, which is implicit in Windows 99, so we should first set up a database file to manage the circuit schematic diagram and PCB layout designed.

② Design of schematic diagram. I mea e ʻike ai i ka pili pūnaewele, pono e loaʻa nā ʻāpana āpau i ka waihona waihona ma mua o ka hoʻolālā kumu. i ʻole, pono e hana i nā mea i koi ʻia ma SCHLIB a mālama ʻia i ka faila waihona. A laila, kāhea wale ʻoe i nā ʻāpana i koi ʻia mai ka waihona puke a hoʻohui iā lākou e like me ka hoʻolālā kaapuni i hoʻolālā ʻia.

③ After the schematic design is completed, a network table can be formed for use in PCB design.

④PCB design. A. CB a me ka hoʻoholo ʻana i ka nui. The shape and size of PCB are determined according to the position of PCB in the product, the size and shape of the space and the cooperation with other parts. Draw the shape of the PCB using the PLACE TRACK command on MECHANICAL LAYER. B. E hana i nā puka hoʻonohonoho, nā maka a me nā helu kuhikuhi ma PCB e like me nā koi SMT. C. Production of components. If you need to use some special components that do not exist in the component library, you need to make components before layout. He maʻalahi ka hana o ka hana ʻana i nā mea i Protel99 SE. Koho i ke kauoha “MAKE LIBRARY” i ka papa kuhikuhi “DESIGN” e komo i ka window e hana ana i ka PONO, a laila koho i ke kauoha “HUAHI HOU” i ka papa kuhikuhi “TOOL” i ka DESIGN. I kēia manawa, huki wale i ka PAD kūlike i kekahi kūlana a hoʻoponopono iā ia i loko o ka PAD i koi ʻia (me ke kinona, ka nui, ke anawaena o loko a me ka Angle o ka PAD, a pēlā aku, a e kaha i ka inoa pin e pili ana o ka PAD) ma ka TOP LAYER me ke kauoha a PLACE PAD a pēlā aku e like me ke ʻano a me ka nui o ka mea maoli. Then use the PLACE TRACK command to draw the maximum appearance of the component in the TOP OVERLAYER, select a component name and store it in the component library. D. Ma hope o ka hana ʻia ʻana o nā mea, e hoʻokō ʻia ka hoʻonohonoho a me nā uea. E kūkākūkā nui ʻia kēia mau ʻāpana ʻelua ma lalo. E. Check after the above procedure is complete. Ma kekahi ʻaoʻao, pili kēia i ka nānā ʻana o ke kaapuni kaapuni, ma kekahi ʻaoʻao, pono e nānā i ke kūlike a me ka hui ʻana o kekahi. The circuit principle can be checked manually or automatically by network (the network formed by schematic diagram can be compared with the network formed by PCB). F. Ma hope o ka nānā ʻana, waihona a hoʻopuka i ka faila. Ma Protel99 SE, pono ʻoe e holo i ke kauoha EXPORT i ke koho FILE e mālama i ka FILE i ke ala i kuhikuhi ʻia a me FILE (ʻo ka IMPORT kauoha e IMPORT i kahi faila iā Protel99 SE). Nānā: Ma ke koho Protel99 SE “FILE” “SAVE COPY AS …” Ma hope o ka pau ʻana o ke kauoha, ʻaʻole ʻike ʻia ka inoa o ke faila i wae ʻia ma Windows 98, no laila ʻaʻole hiki ke ʻike ʻia ka faila ma Resource Manager. He ʻokoʻa kēia mai “SAVE AS …” ma Protel 98. ʻAʻole like kāna hana.

3. Components layout

Ma muli o ka hoʻohana ʻana o SMT i ka umu wela wela e hoʻopili i nā mea hoʻohui, hoʻopili ka hoʻonohonoho ʻana o nā mea i ka maikaʻi o nā hono solder, a laila hoʻololi i ka hua o nā huahana. For PCB design of rf circuit, electromagnetic compatibility requires that each circuit module does not generate electromagnetic radiation as far as possible, and has a certain ability to resist electromagnetic interference. Therefore, the layout of components also directly affects the interference and anti-interference ability of the circuit itself, which is also directly related to the performance of the designed circuit. Therefore, in the design of RF circuit PCB, in addition to the layout of ordinary PCB design, we should also consider how to reduce the interference between various parts of the RF circuit, how to reduce the interference of the circuit itself to other circuits and the anti-interference ability of the circuit itself. Wahi a ka ʻike, ʻaʻole pili ka hopena o ka pōʻai pele ma ka papa kuhikuhi hana o ka papa kaapuni RF ponoʻī, akā ma ka launa pū ʻana me ka papa hana CPU ma kahi nui. No laila, i ka hoʻolālā PCB, pono nui ka hoʻonohonoho kūpono.

General layout principle: components should be arranged in the same direction as far as possible, and the bad welding phenomenon can be reduced or even avoided by selecting the direction of PCB entering the tin melt system; Wahi a ka ʻike, ma kahi o 0.5mm ka hakahaka ma waena o nā mea e kū ai i nā koi o nā mea hoʻoheheʻe piʻina. Inā ʻae ka hakahaka o ka papa PCB, e ākea ka ākea ma waena o nā mea i hiki. No nā paneli pālua, pono e hoʻolālā ʻia kekahi ʻaoʻao no nā ʻāpana SMD a me SMC, a ʻo ka ʻaoʻao ʻē aʻe nā ʻāpana discrete.

Note in layout:

* First determine the position of interface components on the PCB with other PCB boards or systems, and pay attention to the coordination of interface components (such as the orientation of components, etc.).

* Ma muli o ka liʻiliʻi o nā huahana lawelima, hoʻonohonoho ʻia nā ʻāpana i kahi ʻano paʻa, no laila no nā ʻāpana nui aku, pono e hāʻawi i ka mea nui e hoʻoholo ai i kahi kūpono, a noʻonoʻo i ka pilikia o ka hoʻohui ʻana ma waena o kekahi.

* akahele anamanaʻo kaapuni ʻōnaehana, ke kaʻina o ka pōʻaiapuni aaioee (e like me ke kiʻekiʻena amplifier kaapuni, hoʻohuihui kaapuni a me ka demodulation kaapuni, a pēlā aku), a hiki i ka hiki ke hoʻokaʻawale i kēia manawa nā hōʻailona koʻikoʻi a me nā hōʻailona nāwaliwali o kēia manawa, hoʻokaʻawale ka huina hōʻailona digital a me ka hōʻailona analog kaapuni, e hoʻopiha i ka hana like o ke kaapuni e hoʻonohonoho ʻia i kahi papa, no laila e hōʻemi ana i kahi o ka loop loop; Pono e hoʻopili i ka pūnaewele kānana o kēlā me kēia ʻāpana o ke kaapuni ma kahi kokoke, no laila ʻaʻole hiki ke hoʻēmi ʻia ka radiation, akā hiki ke hoʻoliʻiliʻi pū ʻia ka likelika o ke ākea, e like me ka hiki i ka anti-interferensience kaapuni.

* Pūʻulu pūnaewele puni uila e like me ko lākou ʻike i ka hoʻokaulike electromagnetic i ka hoʻohana ʻia. The components of the circuit that are vulnerable to interference should also avoid interference sources (such as interference from the CPU on the data processing board).

4. Uila

After the components are laid out, wiring can begin. The basic principle of wiring is: under the condition of assembly density, low-density wiring design should be selected as far as possible, and signal wiring should be as thick and thin as possible, which is conducive to impedance matching.

No ka pōʻaiapuni RF, ka hoʻolālā kūpono ʻole o ke kuhikuhi laina laina, ka laulā a me ka hoʻokaʻawale ʻana i ka laina i mea e keakea ai ma waena o nā laina neʻe hōʻailona hōʻailona; Hoʻohui ʻia, hāʻawi ka ʻōnaehana mana iā ia iho i ka ʻokiʻoki leo, no laila i ka hoʻolālā ʻana o ka RF circuit PCB pono e noʻonoʻo pono ʻia.

Ke hoʻopili, pono mamao loa nā pilina āpau mai ka palena o THE PCB board (e pili ana i 2mm), i ʻole e hoʻokumu a i ʻole ka makaʻu hūnā o ka uea i ka hana ʻana o ka papa PCB. E ākea ka laina mana i mea e hōʻemi ai i ke kūpaʻa o ka loop. I ka manawa like, pono ke kuhikuhi o ka laina mana a me ka laina honua me ke kuhikuhi o ka lawe ʻana i ka ʻikepili e hoʻomaikaʻi ai i ka hiki anti-interferensi. Pono nā lālani hōʻailona e like me ka pōkole e hiki ai a hoʻemi ʻia ka helu o nā lua i kahi hiki. ʻOi aku ka pōkole o ka pilina ma waena o nā mea, ʻoi aku ka maikaʻi, e hōʻemi i ka hoʻokaʻawale ʻana o nā palena a me ka hoʻopili electromagnetic ma waena o kekahi; For incompatible signal lines should be far away from each other, and try to avoid parallel lines, and in the positive two sides of the application of mutual vertical signal lines; Wiring in need of corner address should be 135° Angle as appropriate, avoid turning right angles.

ʻAʻole pono ke ākea o ka laina e pili pono ana me ka pad, a mamao aku ka laina mai nā mea i hoʻokaʻawale ʻia a hiki i ka hiki ke hōʻalo i ke kaapuni pokole; Holes should not be drawn on components, and should be far away from disconnected components as far as possible to avoid virtual welding, continuous welding, short circuit and other phenomena in production.

In PCB design of rf circuit, the correct wiring of power line and ground wire is particularly important, and reasonable design is the most important means to overcome electromagnetic interference. Quite a lot of interference sources on PCB are generated by power supply and ground wire, among which ground wire causes the most noise interference.

ʻO ke kumu nui ke maʻalahi o ka uea honua e hoʻonāukiuki i ka electromagnetic ka impedance o ka uea honua. When a current flows through the ground, a voltage will be generated on the ground, resulting in the ground loop current, forming the loop interference of the ground. When multiple circuits share a single piece of ground wire, common impedance coupling occurs, resulting in what is known as ground noise. Therefore, when wiring the ground wire of the RF circuit PCB, do:

* ʻO ka mea mua, ua mahele ʻia ke kaapuni i nā palaka, hiki ke hoʻokaʻawale ʻia ke kaapuni RF i ka hoʻonui pinepine ʻana, ka hoʻohuihui ʻana, ka hoʻohaʻahaʻa ʻana, ka haʻalulu kūloko a me nā ʻāpana ʻē aʻe, e hāʻawi i kahi wahi kūmole hiki ke loaʻa no kēlā me kēia kaapuni kaapuni honua, no laila ka hiki ke hoʻoili i ka hōʻailona ma waena o nā modula kaapuni. A laila hōʻuluʻulu ʻia ia ma ke kiko kahi e hoʻopili ai ka RF circuit PCB i ka honua, i hōʻuluʻulu ʻia ma ka honua nui. No ka mea aia wale nō kahi kiko kuhikuhi, ʻaʻohe mea hoʻopili impedance maʻamau a no laila ʻaʻohe pilikia pili ʻelua.

* Kahi kikoʻī a me kahi ʻāpana analog a hiki i ka hoʻokaʻawale ʻana o ka uea honua, a me ka honua uila a me ka honua analog e hoʻokaʻawale, a laila pili loa i ka honua lako.

* E nānā pono ka uea honua i kēlā me kēia ʻāpana o ka pōʻaiapili i ka lula pae hoʻokumu hoʻokahi, e hoʻoliʻiliʻi i ka wahi loop loop, a me ka helu kaapuni kānana pili pono ma kahi kokoke.

* Inā ʻae kahi, ʻoi aku ka maikaʻi o ka hoʻokaʻawale ʻana i kēlā me kēia module me ka uea honua e pale ai i ka hoʻopili ʻana o ka hōʻailona ma waena o kekahi.

5. Panina

Aia ke kī o ka hoʻolālā RF PCB i ka pehea e hōʻemi ai i ka radiation radiation a pehea e hoʻomaikaʻi ai i ka hiki anti-interferensi. ʻO ka hoʻonohonoho kūpono a me nā uea ka hōʻoia o DESIGNING RF PCB. ʻO ke ʻano i hōʻike ʻia i loko o kēia pepa he mea kōkua e hoʻomaikaʻi i ka hilinaʻi o ka hoʻolālā PCB circuit PCB, hoʻonā i ka pilikia o ka hoʻopili electromagnetic, a hoʻokō i ke kumu o ka uila electromagnetic.