频谱仪探头制作 – 探针、probe、loop

频谱仪一般50欧电缆，让线缆形成一个闭合的回路，并要留有磁通量通过的面积即可，从而形成一个简易的等效探头。

频谱仪LOOP探头
一般是找一根比较好的射频线缆拨开，将里面的芯绕成圆环状接在外围的地线上即可。

E- and H-Field Probes – The close field probes are constructed from semi-rigid coax (see photo above). The simplest design for an h-field probe merely takes the center conductor, bends it around and solders it to the shield in a loop. The larger the loop diameter, the more sensitivity, but less resolution. Because these probes are geometrically unbalanced, a small ferrite choke clamped around the coax near the connector will help keep common-mode currents from flowing along the outside of the shield and disrupting your measurements. The e-field probe is constructed by stripping away a small part of the outer shield. It’s wise to cover the probes with an insulating material, such as “tool dip” (red coating above) to avoid shorting the product under test. Currently, for a “quick and dirty” probe, you may also use a length of standard coax cable. Strip out the center conductor, bend it around in a loop and solder it the the braided shield (as in the “micro” loop pictured above).

频谱仪Probe探针
可以用一个高压隔离电容，串联在50ohm同轴电缆的芯线上，即电容一头接同轴线缆靠近频谱这端、另外一头用一块PCB固定，然后用一根比较硬的钢针连接，然后就可以用了。