Microwave Journal's sample issue

ure 4 shows the measured inductance
and insertion loss values for these
different wire lengths. From these
measurements, it clearly shows that
the longer wire will induce a larger in-
ductance and the values will increase
slowly with increased frequency. The
10 mils height wires, with 60 and 25
mils lengths, provide approximately
1.29 and 2.98 nH at 10 GHz before
de-embedding, respectively. How-
ever, since the wire inductance and
the parasitic capacitance from the test
pattern resonate at a specific frequen-
cy, the inductance becomes a capaci-
tance above the measured frequency
ƒSR. The 25 mils long wire has an ƒSR
greater than 20 GHz, which is approx-
imately 7 GHz higher than for a 75
mils wire length. Undoubtedly, these
values depend on the design of the
test pattern. A designed test pattern
with lower (higher) parasitic capaci-
tance increases (decreases) the wire

Microwave components from Herley General Microwave

Your time-trusted source I-Q Vector Modulators

inductance value and its ƒSR. For a simple comparison, these data can be objectively compared to other round or ribbon wires, but may not be too accurate for other cases.

Meanwhile, the wire length also affects the insertion loss directly. The measured insertion loss of the long wire shows an insertion loss 2 dB higher than that of the short wire at 20 GHz. It clearly indicates that the wiring length must be as short as possible when the operating frequency goes up above 10 GHz. The higher insertion loss is due to the impedance mismatch. In order to further compare the ball bonding and wedge bonding for the same cross-section area wires, two wires with 60 and 25 mils length were measured for comparison. From the measured results displayed in Figure 5, it is shown that two wires using ball and wedge bonding with the same cross-section have almost the same frequency response up to 20 GHz. It clearly points out that the bonding type does not affect the high-frequency performance dramatically. However, the wiring shape is the most important factor dominating the wiring characteristics.