Then, the number of lumped elements of impedances or admittances at midpoint can be reduced when [Y.sub.ses] and [Y.sub.shs] are only

parallel resonance and [Z.sub.ses] and [Z.sub.shs] are only series resonance such as CRLH TL topology.

When do you need to worry about

parallel resonances? What roles do power and ground planes play in the impedance of power delivery network (PDN)?

[L.sub.1] and [C.sub.gs] of M2 form a

parallel resonance to perform simply the interstage matching.

Simplified scheme with current source and 50 Hz

parallel resonance circuit ([L.sub.PC] = 1 H, C = 10.13 [micro]F, p = 22000 V/650 V).

We may explain this in two reasons: Firstly as the resistance of [f.sub.0], 120 ohm is good enough to get the return loss better than -6dB; Secondly resistances of [f.sub.0l] and [f.sub.0h] (Series resonance) are lower than that of [f.sub.0] (

Parallel resonance. Please refer to Figure 2(c)), so properly choosing a bigger resistance for [f.sub.0] will make sure that [f.sub.0l] and [f.sub.0h] locate around 50 ohm.

Based on the above discussion, in this article, a compact printed antenna with a

parallel resonance structure for penta-band WWAN tablet computer application is presented.

For simplicity, it is assumed that the antenna can be presented as a

parallel resonance circuit, with the inductor L, the radiating element (see Figure 3).

For lossless equivalent LC circuit model adopted, series resonance frequency and

parallel resonance frequency are obtained from immittances characteristic, which is utilized to extract the LC parameters.

This work concentrates on a typical series-resonance contactless power supply circuit with a

parallel resonance compensator.

However, for drastic variation impedance, the load is in series resonance or

parallel resonance within a very narrow band, etc., the AAV may not accurately represent the overall impedance level within the frequency range we care.

The frequency of the

parallel resonance on the 14 mil FR4 is about 2 GHz higher than for the 59 mil case.