Mgbe etinyere mgbama ugboro redio dị elu/microwave n’ime PCB sekit, ọnwụ nke sekit ahụ n’onwe ya na ihe sekit ga-esi na ya pụta ga-emepụta ụfọdụ okpomọkụ. Nke ka ọnwụ na-abawanye, ike dị elu na-agafe na ihe PCB, na ka ọkụ na-esiwanye ike. Mgbe okpomọkụ na-arụ ọrụ nke sekit karịrị ọnụ ahịa echere, sekit nwere ike ịkpata nsogbu ụfọdụ. Dị ka ọmụmaatụ, ahụkarị paramita ọrụ MOT, nke a maara nke ọma na PCBs, bụ kacha arụ ọrụ okpomọkụ. Mgbe okpomọkụ na-arụ ọrụ karịrị MOT, arụmọrụ na ntụkwasị obi nke sekit PCB ga-eyi egwu. Site na nchikota nke ihe nlere elektrọnik na nha nnwale, ịghọta njirimara ọkụ nke RF microwave PCBs nwere ike inye aka zere mmebi arụmọrụ sekit na mmebi ntụkwasị obi nke oke okpomọkụ kpatara.

Ịghọta ka ntinye ntinye na-apụta na ihe sekit na-enyere aka ịkọwa nke ọma ihe ndị dị mkpa metụtara arụmọrụ okpomọkụ nke sekit PCB dị elu. Edemede a ga-ewere sekit nnyefe microstrip dị ka ihe atụ iji kwurịta ahịa-offs metụtara arụmọrụ okpomọkụ nke sekit. N’ime sekit microstrip nwere PCB nwere akụkụ abụọ, mfu gụnyere mfu dielectric, ọnwụ onye nduzi, mfu radieshon, na mfu nke ntapu. Ihe dị iche n’etiti ihe dị iche iche ọnwụ bụ nnukwu. Ewezuga ole na ole, mfu nke sekit PCB dị elu na-adịkarị ala. N’isiokwu a, ebe ọ bụ na ọnụ ahịa nkwụsị nke ntanye dị ntakịrị, a ga-eleghara ya anya maka oge a.

Ọnwụ radieshon

Radiation loss depends on many circuit parameters such as operating frequency, circuit substrate thickness, PCB dielectric constant (relative dielectric constant or εr) and design plan. As far as design schemes are concerned, radiation loss often stems from poor impedance transformation in the circuit or electromagnetic waves in the circuit. The difference in transmission. Circuit impedance transformation area usually includes signal feed-in area, step impedance point, stub and matching network. Reasonable circuit design can realize smooth impedance transformation, thereby reducing the radiation loss of the circuit. Of course, it should be realized that there is the possibility of impedance mismatch leading to radiation loss at any interface of the circuit. From the point of view of operating frequency, usually the higher the frequency, the greater the radiation loss of the circuit.

The parameters nke sekit ihe metụtara radieshon ọnwụ bụ tumadi dielectric mgbe niile na PCB ihe ọkpụrụkpụ. The thicker na sekit mkpụrụ, ukwuu ohere nke ịkpata ọnwụ radieshon; na ala εr nke PCB ihe onwunwe, ukwuu radieshon ọnwụ nke sekit. Comprehensively-erikpu ihe e ji mara, ojiji nke mkpa sekit substrates nwere ike iji dị ka a ụzọ dechapụ radieshon ọnwụ kpatara ala εr sekit ihe. Mmetụta nke sekit mkpụrụ ọkpụrụkpụ na εr na sekit radieshon ọnwụ bụ n’ihi na ọ bụ a ugboro-adabere ọrụ. Mgbe ọkpụrụkpụ nke mkpụrụ sekit anaghị agafe 20mil na oge ọrụ ya dị ala karịa 20GHz, ọnwụ radieshon nke sekit dị obere. Ebe ọ bụ na ọtụtụ n’ime ihe ngosi sekit na nha nha n’isiokwu a dị ala karịa 20GHz, mkparịta ụka dị n’isiokwu a ga-eleghara mmetụta nke ọnwụ radieshon na kpo oku sekit anya.

Mgbe eleghara ọnwụ radieshon n’okpuru 20GHz, ntinye ntinye nke eriri nnyefe microstrip gụnyere akụkụ abụọ: ọnwụ dielectric na ọnwụ onye nduzi. Ọnụ ọgụgụ nke abụọ na-adabere na ọkpụrụkpụ nke mkpụrụ sekit. Maka ihe ndị dị gịrịgịrị, ọnwụ onye nduzi bụ isi ihe. N’ihi ọtụtụ ihe kpatara ya, ọ na-esiri ike ịkọ n’ụzọ ziri ezi ọnwụ onye nduzi. Dịka ọmụmaatụ, ịdị elu dị elu nke onye nduzi nwere mmetụta dị ukwuu na njirimara nnyefe nke ebili mmiri electromagnetic. Ọdịiche dị n’elu nke foil ọla kọpa agaghị agbanwe ọ bụghị naanị na ịgbasa ikuku elektrọnik mgbe niile nke sekit microstrip, kamakwa ọ na-abawanye ọnwụ onye nduzi nke sekit. N’ihi mmetụta akpụkpọ ahụ, mmetụta nke nhụsianya ọla kọpa na ọnwụ onye nduzi na-adaberekwa ugboro ole. Ọgụgụ 1 tụlere mfu ntinye nke sekit mgbasa ozi microstrip 50 ohm dabere na ọkpụrụkpụ PCB dị iche iche, nke bụ 6.6 mils na mils 10, n’otu n’otu.

The simulation results are obtained using Rogers Corporation’s MWI-2010 microwave impedance calculation software. The MWI-2010 software quotes the analytical equations in the classic papers in the field of microstrip line modeling. The test data in Figure 1 is obtained by the differential length measurement method of a vector network analyzer. It can be seen from Fig. 1 that the simulation results of the total loss curve are basically consistent with the measured results. It can be seen from the figure that the conductor loss of the thinner circuit (the curve on the left corresponds to a thickness of 6.6 mil) is the main component of the total insertion loss. As the circuit thickness increases (the thickness corresponding to the curve on the right is 10mil), the dielectric loss and the conductor loss tend to approach, and the two together constitute the total insertion loss.

The circuit material parameters used in the simulation model and the actual circuit are: dielectric constant 3.66, loss factor 0.0037, and copper conductor surface roughness 2.8 um RMS. When the surface roughness of the copper foil under the same circuit material is reduced, the conductor loss of the 6.6 mil and 10 mil circuits in Figure 1 will be significantly reduced; however, the effect is not obvious for the 20 mil circuit. Figure 2 shows the test results of two circuit materials with different roughness, namely Rogers RO4350B™ standard circuit material with high roughness and Rogers RO4350B LoPro™ circuit material with low roughness.

For thinner substrates, the use of smooth copper foil can significantly reduce the insertion loss. For the 6.6mil substrate, the insertion loss is reduced by 0.3 dB due to the use of smooth copper foil at 20GHz; the 10mil substrate is reduced by 0.22 dB at 20GHz; and the 20mil substrate, the insertion loss is only reduced by 0.11 dB.

This means that when the circuit is fed with a certain amount of RF microwave power, the thinner the circuit will generate more heat. When comprehensively weighing the issue of circuit heating, on the one hand, a thinner circuit generates more heat than a thick circuit at high power levels, but on the other hand, a thinner circuit can obtain more effective heat flow through the heat sink. Keep the temperature relatively low.

Iji dozie nsogbu kpo oku nke sekit, ezigbo mkpa sekit kwesịrị inwe àgwà ndị a: obere ihe na-efu nke ihe sekit, ezigbo ọla kọpa mkpa elu, ala εr na elu thermal conductivity. E jiri ya tụnyere ihe sekit nke elu εr, onye na-eduzi obosara nke otu impedance nwetara n’okpuru ọnọdụ nke ala εr nwere ike ibu ibu, nke bara uru iji belata nkwụsị nke nchịkwa nke sekit. Site n’echiche nke dissipation okpomọkụ sekit, ọ bụ ezie na ọtụtụ elu-ugboro PCB sekit substrates nwere nnọọ ogbenye thermal conductivity ikwu na-eduzi, thermal conductivity nke sekit ihe ka bụ ihe dị oké mkpa oke.

A kọwawo ọtụtụ mkparịta ụka gbasara thermal conductivity nke sekit substrates n’isiokwu ndị mbụ, na isiokwu a ga-ehota ụfọdụ nsonaazụ na ozi sitere na isiokwu ndị mbụ. Ọmụmaatụ, ndị na-esonụ equation na Figure 3 na-enyere aka ịghọta ihe ndị metụtara thermal arụmọrụ nke PCB sekit ihe. Na nhata, k bụ thermal conductivity (W / m / K), A bụ mpaghara, TH bụ okpomọkụ nke isi iyi ọkụ, TC bụ okpomọkụ nke isi iyi oyi, na L bụ ebe dị anya n’etiti isi iyi ọkụ na isi iyi oyi.