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Via stub resonance frequency

Benefits of Millet And Its Side Effects

Normal conducting RF cavity resonance control is performed via a slug tuner, while superconducting TESLA-type cavity resonance control is performed via piezo actuators. 8. Nov 03, 2017 · This stub would look like a capacitor on the TDR plot and can create resonance phenomena. the level of influence of the variables stub length and antipad size at various frequencies up to 40GHz. A sonic band gap based on the locally resonant phononic plates with stubs. The frequency of the quarter-wave-length-resonance is correlated to the stub length as well as the increase of the insertion loss well below the resonance point is discussed. We all tend to agree that high-speed signals are significantly degraded if the resonance frequency of a via stub Via Stub – The via stub resonance can be removed or pushed up to a higher frequency by back-drilling the via – The stub resonance at 15GHz with 3rdlayer stripline case is completely removed by the back-drilling © Keysight Technologies 2017 Below this portion, however, the unused stub, a conductive portion of the via not connected in series with the circuit, presents itself as an unterminated transmission line with significant signal degradation around its resonant frequency (determined by the quarter wavelength of the structure. is the frequency of a sine wave, and the time delay (TD) through the stub portion equals a ¼ - wavelength, then when it reflects at the bottom and reaches the junction again, it will be delayed by ½ a cycle. Figure 16. Jul 17, 2018 · In order to transmit the signal faithfully in the presence of a via stub, we require that the stub’s first resonant frequency should be greater than the fifth harmonic. 7. stub resonator and loaded it by replacing the shorter stub by a capacitor while simultaneously replacing the longer one by a quarter-wave length stub and a capacitor [4]. 1. Indeed, at very high data rates, even after the via stubs are The following figure shows the reflection coefficient of the above stubs, versus frequency, starting at DC and sweeping up to the quarter-wave frequency (10 GHz, denoted by markers M1 and M2. For example, the stub's length may be increased by an integer multiple of half-wavelengths at a particular frequency and its input susceptance at this frequency will not change. ucla. The SI Perils of Power Via Stubs . 65. Oct 06, 2014 · If the stub is 0. Via impedance is the impedance seen between the plus (+) and path and the return path for each frequency may have a different Via Stub Resonance. We first introduce slow-light subwavelength plasmonic waveguides based on plasmonic analogues of periodically loaded transmission lines and electromagnetically induced transparency. ) Oct 18, 2019 · For a typical driven damped mechanical oscillator, the resonant frequency is defined in the following equation: Resonant frequency vs natural frequency of a driven damped mechanical oscillator . The relationship between the quarter  12 Oct 2016 This is due to the via stub acting as a transmission line antenna, which has a resonant frequency determined by the quarter wavelength of the  Figure 2 shows that the higher resonance frequency increased with the height, The tuning stub, represented by , is connected to the feeding source via the  1 Feb 2018 Distance from signal via to stitching vias is about quarter of effect onset frequency (no DC) – it is not possible Reality: Stub resonance on. The measured resonant frequency, return loss, insertion loss and fraction using left-handed transmission line (LH-TL) made up of IDC and shorted stub  stubs may be carried out using Mathcad files at a single frequency and calculate the Q of that impedance using and 8 are equal at the resonant frequency of. The zeroth order resonance frequency of proposed filter is guarded May 13, 2003 · Abstract: We present results of study of the resonance stub effect occurring in a transition from a through via hole to a stripline in a multilayer printed circuit board (PCB). via stubs that degrade signal integrity. 25 Gbps −Higher Resonant Frequency Via Stub About Apr 06, 2013 · Other related posts: » [SI-LIST] Resonance due to stitching via ground stubs- Jason. resonance), B1 and B2 (via-to-via trace resonance), B2 and C2 (via 2 stub resonance), and B2 and A2 (via 2 thru resonance). Figure 3: Return loss vs. Variation of the length of the first stub, keeping the length of the second stub constant, re-sults in ten different resonant frequencies as shown in Fig. 63% and a maximum transmission loss of −1. 3/BR[Gbps], or, Len[cm] 0. Table 2: Resonant frequency deviation due to variation in the width of stubs (Inner ring kept constant) Width of stub (mm) Apr 16, 2014 · The quarter wavelength rule is a rule that acoustic engineers use in calculating the space requirements for low frequency absorption. The deeper curve (brown) is calculated with the extracted t parameters, at the extracted resonance frequency, and its minimum Even lower frequency bit rates can suffer from via stub resonances, if their bandwidths are riding on the edge of the resonance curve. 39 dB, whereas the plane wave with a 30° incidence angle shows a resonance frequency variation of up to 1. Vias as a dominant source of discontinuities; Why two discontinuities cause more problems than just one; The two important structures in a via; Why the via stub is usually the biggest problem; The stub resonant frequency; Introducing the HyperLynx lab on via stubs; Designing transparent vias; Introducing When excited at high frequency, the stub incurs some return loss, reflecting some of the incident wave back into the via barrel and along the interconnect. The relative  frequency of the signals passing through them. Vias should be back-drilled in order to prevent standing waves from forming in the via stub as a resonating signal in a stub can act as a strong radiator or antenna. Apr 19, 2019 · Aside from increasing impedance, any stubs left on a via will act as high frequency resonators. A precise controlling for the mount of a gas in certain place can be vital in quality for industrial process, for security, and for human health applications. e. A via stub acts as a transmission line antenna , and has a resonant frequency determined by the quarter wavelength of the  At frequencies that are sufficiently high, this via open stub may load the signal transmission line slight discrepancy (0. In fact, at this point the total channel loss is close to 30dB. The most effective way of eliminating this problem is to move the via stub resonant frequency as high as possible, by using as short a via stub as possible. Reflection Caused by Stubs in a Via. 2 mm thick board, a via stub (3. © Keysight strip layer down), the stub resonance frequency can be pushed up to a higher  8 Mar 2017 We worry about via stubs in high-speed designs because they cause unwanted resonant frequency nulls which appear in the insertion loss plot  14 Mar 2018 We all tend to agree that high-speed signals are significantly degraded if the resonance frequency of a via stub attached to the signal path  the usable bandwidth of the signal. 1. This makes the antenna look longer or smaller. Key advantages include: We review some of the recent research activities on plasmonic devices based on metal-dielectric-metal (MDM) stub resonators for manipulating light at the nanoscale. By using higher order line codings with a lower fundamental frequency it is possible to operate the channel at higher data rates by keeping the fundamental frequency away from the stub resonances. Oct 23, 2014 · The effect of a stub routing topology, from whatever source, can suck out a significant fraction of the signal energy at and near the quarter wave stub resonance frequency. A 3D full wave simulation tool, such as O-Wave, is required to accurately capture the resonance due to long via stubs. Latest CISCO TECHNOLOGY, INC. If the stub length is greater than this, it does not mean the design will not work at 5GB/s. The resonance significantly increases insertion loss and turns the signal path off at the resonance frequency. 4 GHz. PCB FABRICATION Backdrilling and Blind/Buried Via Formation Preserving signal integrity. If the incident signal is a continuous AC waveform, these reflections will mix with more of the oncoming incident waveform to produce stationary waveforms called standing waves. , Los Angeles, CA90095-1594, USA E-mail: sanada@ieee. The first and second passbands are formed by a multi-stub loaded resonator. 08:1. At this load, the phase response of the stub tuner can be measured using a weak. Enter your desired frequency (MHz) of operation (i. The stubs are about 75 mils. These problems with signal resonance are typically mitigated by back-drilling the stub during assembly. A through via can affect the signal propagation at a given frequency due to its stub resonance. 0完成操作,2014年重新撰寫, 以SIwave 2014將模擬結果更新,介紹貫孔的stub與NFP (Non-Functional Pad)效應 。. The two modeling results agree appmximately, with a slight discrepancy (0. If this scenario occurs, the main wave and the reflected wave ap-pear 180 out of phase, producing de-structive signal cancellation. Interaction Between Main Line Standing Waves and Side Branch Resonance Frequencies Peter McKinni;] Brett Miller and Arthur Ruggles University oj JenRessee, Department of Nuclear Engineering, Knoxville aruggles@utk. In the via design, we see the via stubs when the traces transition from the microstrip layer to the stripline layer. Advantages and disadvantages of these designs as well as the solution to their resonance frequency shift problems are discussed as well. To ensure that the new stub Natural Frequency Resonance is an universal phenomenon. Namely, the stub perturbs the resonances of the conventional 6 Oct 2014 Remember : before you start using rules of thumb, be sure to read the What is the quarter-wave stub resonant frequency for a via stub that is  17 Jul 2018 A via stub acts like a resonant circuit with a specific resonant frequency at which it stores maximum energy within it. 23 GHz during a V G - V SD 2D sweep. It also demonstrates the effect of localised coupling: if instead of the signal injected via This effect for via structures including ground vias is estimated by numerical simulations and measurements in the frequency band up to 20 GHz. We chose to work Sep 23, 2004 · The inductance and resonance frequency of birdcage coils are dependent on (and limited by) the dimension of the end rings, which in turn define the diameter of the coil. Transmissibility peaks can be automatically detected from a sine sweep, and then dwell tests run at the detected resonance frequencies for a specified time  本文始於2009以SIwave v3. Therefore, the via stub on this connection should be made as short as possible. capacitance and a meander line along with a rectangular stub gives shunt inductance and capacitance. layout considerations. 3 mm (12 mils) Die, Package, PCB Co-sim Stub Resonance Nov 03, 2017 · Via stub reduction by back drilling or use of blind/buried vias, via transition optimization by ground via and anti-pad optimization become necessary. ② Resonance: jX = 0, (By adding XC or XL from the coaxial cable, the resonance frequency can be shifted to almost all frequencies in the table above). Note that resonance can only occur when the natural frequency is greater than the damping rate, multiplied by the square root of 2. Their resonant frequency can be roughly estimated by the isolated 'spring-mass' model [15, 22]: , where k is the effective elastic constant and m is the mass of open stub. At this point it is 180 degrees out of phase, and cancels most of the original signal. Selectivity , sensitivity, and foot print are the main characteristics in designing any gas sensors. 1 Oct 2014 With respect to question 7, I shall define a “good” launch as a connector/launch that has a return loss of 20dB or better at the maximum frequency  31 May 2017 In this video, I show how to measure peak resonance frequency for a sub system, using a voltmeter, test tones and a 20w 5ohm resistor. org, caloz@ee. The via-stub resonator is designed to reproduce a dielectric constant value of a known material in a simulation. ) As an interconnect component of a  Sine Resonance Track & Dwell (SRTD) option will sweep through a frequency range and then select the top 10 resonances based on your resonance criteria. We identified that the resonant frequency depends on the length of the stub. If you have no particular preference within a given ham radio band, then simply enter its center frequency (i. If one of these frequency nulls happen to randomly line up at or near the Nyquist frequency of the bit rate, it will result in a high bit-error-rate; even link failure. 3 May 2007 A high-frequency signal that propagates through a long line on the PCB disadvantage of daisy chain routing is that stubs, or short traces, are To filter power supply noise, use a non-resonant, surface-mount ferrite. Similarly, variation of length of the second stub, keeping A recently developed form of extremum seeking for time-varying systems is implemented in hardware for the resonance control of radio-frequency cavities without phase measurements. Simulation results show that two sharp Fano resonant (Fano(1,1) and Fano(2,1)) modes can be formed by the interactions between the broad MIM stub resonance and the very ① The resonance frequency is not always the same as the minimum SWR frequency. 16, which is considerably higher than the published bulk Dk of 3. QRV. Probably one of the few exceptions is via stubs. edu Stub Tuner Matched RF Amplifier 0 1 resonant resonant LC ω = Series Resonant Ckt at Operating Frequency: Short Ckt at Resonance, Open Circuit at DC λ /4 Transformer: Transforms Short Circuit at Resonance to Open circuit at BJT Collector Thus Isolating RC from RF Signal Path Stub tuners of two types: Base-Side: Open Circuit Stub w/ In summary, sharp Fano resonances in the plasmonic waveguide system composed of a MIM stub coupled with a plasmonic square cavity resonator were proposed and investigated. EMC radiation from the stub end, reduced excitation of resonance modes and reduced via-to-via crosstalk. A  15 May 2015 of the line Z0 at one specific resonance frequency. Still, one can insert the MUT (i. In fact, as you point out, the issue of the distortion from the via stubs is another critical factor influencing the BER in high-speed serial links. its resonant frequency (determined by the quarter wavelength of the structure. Ways to  Many of our PCB design customers ask us about modelling plated through hole frequency, you need to take steps to reduce or remove the effects of via stubs. edu Abstract Acoustic standing waves may be established in main gas delivery lines that are caused by resonance in branch lines. 13 Apr 2015 Highlight from the Osstell Scientific Forum at EAO Resonance Frequency Analysis (RFA) The story so far - from the first experimental equipment  12 Jul 2012 (Note that the important concept here is not data rates in time domain, but frequencies in frequency domain. The free end of the stub is either left open-circuit or (always in the case of waveguides) short-circuited. There are topics where even well-seasoned signal-integrity experts cannot agree on a unified answer. A via dielectric constant in an x and y plane is calculated based on the resonance frequency. 4. This problem is especially problematic in multilayer boards with high layer count, wherein a via used to pass between two neighboring layers leaves a solid stub that passes through the remaining layers. In both cases, the structures consist of a MDM Whenever there is a mismatch of impedance between transmission line and load, reflections will occur. fluid) through the substrate [10, 11]. The structure that is comprised of the segments l2, l3, and l4 and is short-circuited on its left side is a stub-loaded quarter-wavelength resonator which exhibits dual-mode behaviour. SD) collected at the xed frequency 3. When the diameter is very large, as is the case for body coils, the axial length of the coil must be sufficiently shortened to achieve resonance at the desired operational Designing for System Scalability From 622 Mbps to 6. 4 GHz) near the resonant frequency, which may partly result hm neglecting the capacitive coupling between the via body and the ground planes. This effect for via structures including ground vias is estimated by numerical simulations and measurements in the frequency band up to 20 GHz. 25 Gbps −Higher Resonant Frequency −Board Thickness & Via Stub Issues Sep 01, 2006 · Fixing the via stub problem just allows you back in the game to then worry about the rise time degradation from the frequency dependent dielectric loss. Using the rule of thumb for quarter-wave length stub resonance in FR4, we expect a resonance at close to 20 GHz, close to the dip shown in the channel. 75/BR[Gbps]. Backdrilling and Blind/Buried Via Formation techniques eliminate via stubs that degrade signal integrity. Therefore, it exhibits a resonance at the frequency at which its electrical length is equal to π/2. Ellison » [SI-LIST] Re: Resonance due to stitching via ground stubs- Bradley Brim » [SI-LIST] Re: Resonance due to stitching via ground stubs- Antonis Orphanou HSDD-40-30 Lecture 12 Vias and the PDN. 55). This sets the stub resonance frequency to a very high value and also minimizes reflection from the stub itself, which suppresses EMI. 120 inches in FR4 material with a Dkeff of 4. 9 mm long) may introduce a resonance at approximately 6. Sep 13, 2018 · Graph lines 112 and 113 shift the resonant frequency higher because Z1<Z2. If we know the bandwidth of the signal, we can estimate the longest stub length before the Dec 03, 2009 · FIG. On printed circuit boards vias are a major cause of signal distortion. But over a frequency band, the susceptance will vary considerably more than if the extra length had not been added. Published 25 August 2010 • IOP Publishing and Deutsche Physikalische Gesellschaft New Journal of Physics, Volume 12, August 2010 A Compact Triple-Band Passband Filter Using Multi-Stub Loaded Resonator and Asymmetrical SIRs Jun-Mei Yan1, 2, *,Liang-ZuCao1, 2, and Xing-Guo Wang1 Abstract—This letter presents a compact triple-band passband filter with high frequency selectivity. El-Bakly ABSTRACT To properly design the microwave components such as transmission lines, filters, capacitors, inductors, and many others, it is important to know the characteristics of the construction materials at microwave frequencies. Figure IO. At this resonance frequency, insertion loss is as high as −30 dB, Mar 31, 2019 · Via stubs act like hanging wires and can radiate strongly at high frequencies. 25GHz. into a fluid . The bandwidth of the Signal Integrity Tips and Techniques Using TDR, VNA and Modeling 5 GBit 0. Ways to alleviate problems in the design of interconnections embedded in multilayer PCBs due to the resonance stub effect and possible applications of the effect in microwave filtering are traced. the position of the inner stub) using the distance between resonators,. We see in this rule of thumb that if we want to engineer a higher dip frequency, we must make the stub length shorter. Conversely, 115 and 116 shift the resonant frequency lower because Z1>Z2. Istvan Novak, Oracle, March 2018 . Decreasing via stub length by backdrilling significantly reduces resonance modes and reduced via-to-via crosstalk. Transmission curve 91 shows a 5. 3. 7 illustratively shows the effects of the present invention on electrical performance of a via field. On the negative side Resonance has led to many failures and disasters. Estimating Via Stub Resonance Frequency Via Stub Back-Drilling Stub Resonance Electric and Magnetic Field View Jan 19, 2015 · Spoiler summary: The maximum acceptable stub length is roughly Len[in] 0. resonant unit. The plane wave with a 0° incidence angle shows a resonance frequency variation below 0. If you know the length of the stub, you can predict the fundamental As an example, for a 24-layer and 4. Simulations of different designs of the coplaner coupled stripline resonator using different stub dimensions are presented. . The measured insertion loss has 0. 15 for the 40 meter band). 8 Mar 2020 The longer the stub the more resonant frequencies fit into the frequency effect of a stub (in this case an 0. 3 cm, the quarter-wave stub resonance frequency will be about 3 GHz. The dangling via stub can be trimmed by drilling from the back side. In microwave and radio-frequency engineering, a stub or resonant stub is a length of transmission line or waveguide that is connected at one end only. May 15, 2015 · Γ is measured near the resonance frequency with a probe power chosen to be so low that no out-of-equilibrium charges are induced when applying microwave signal to the stub tuner. Long via stubs creates bad signal integrity at high frequencies A longer via stub will cause higher capacitance and lower inductance, and thus, lower characteristic impedance. 2 GHz. If possible, the stub should be eliminated entirely by backdrilling. Read on to understand this failure mode. The Reactance X is the imaginary Part of the complex Impedance Z Calculation of Capacity C and Inductivity L Enter any two known values and press "Calculate" to solve for the others. This effect for via structures including ground vias is estimated by numerical simula- tions and measurements in the frequency band up to 20 GHz. May 13, 2003 · Abstract: We present results of study of the resonance stub effect occurring in a transition from a through via hole to a stripline in a multilayer printed circuit board (PCB). This resonance is undesirable for signal transmission because it causes increased losses at frequencies near it. Thus, you must “back drill” such vias after the PCB is fabricated. ) The open circuit S11, plotted on the left) sweeps from an open to a short, while the short circuit (S22, on the right) sweeps from a short to an open. In this post I show you how to apply it to help address the acoustic issues you face in your studio. It has been demonstrated that designs using a fork-shaped stub are an However, before the effective tuning, the multiple resonant frequency bands do not  When using short circuit stubs, place a capacitor between the stub and ground to produce RF path to ground Series Resonant Ckt at Operating Frequency:. Mourad Oudich 1, Yong Li 2, Badreddine M Assouar 1,3 and Zhilin Hou 2. 6 mm (24 mils) Via Zo 10 GBit 0. 60dB and return loss above 15dB with 3dB fractional bandwidth 74. Gas sensing play an important role in various fields such as environmental, medical, and for industrial applications. The resonant frequency or bandwidth of a transmission line or PCB trace is inversely proportional to the length of via stub. RF/Microwave Signals are One Frequency or a Band Flat Stripline Using PCB Techniques right after WWII λ/4 Stub is Series Resonant Circuit at Frequency. compact resonator whose resonance frequencies can be separately selected [22] . less transmission) at lower frequencies. 5+Designer/Nexxim v4. EE371 Lecture 16 20 Reflections From Via Stubs Additional sources of reflections : stubs » Vias - particularly on thick backplanes » Package plating stubs Top layer signaling results in large via stub 0 2 4 6 8 10-60-50-40-30-20-10 0 frequency [GHz] Attenuation [dB] 9" FR4, via stub 26" FR4, via stub 26" FR4 9" FR4 The added stub is designed to improve the Q values of the structure resonances. What is Frequency Resonance? Product design and Structural design have benefited from these failures. The aim was to demonstrate the importance of such structure in the independent control of the quality factor and the resonance frequency. C1/C3 represents the capacitance between the top/bottom signal via pad and the ground structure, comprised of two ground via pads on the same layer and the adjacent ground plane as shown in Fig. The positive side of this Resonance is what makes many of our consumer devices work. Via Stub Resonance @ Nyquist Freq. frequency plot for variation in width of stub. stub of about 15mm height, emissions were below the noise floor except very near to the resonant frequency. All the measured dI=dV SD values (green diamonds) correspond to less than 30 S, ex-cept for one point taken from the near-match curve in (b). At the quarter-wave frequency, the open-ended stub looks like a short and produces nulls of transmission. It is generated by the unused part of the via below the signal layer where a new stripline comes out Jan 19, 2015 · The effect of a stub routing topology, from whatever source, can suck out a significant fraction of the signal energy at and near the quarter wave stub resonance frequency. A method for measuring the via dielectric constant using the via-stub resonator is also disclosed herein. Depending on just how much longer it is means there will be less than optimum eye opening at the receiver. (This makes sense since the stub length is the same at 52. Estimating Via Stub Resonance Frequency Via Stub Back-Drilling Stub Resonance Electric and Magnetic Field View Designing for System Scalability From 622 Mbps to 6. 0 to ensure the first resonant frequency null is greater than 5 times the Nyquist frequency of the bit rate. Improved frequency as a result of Backdrilling techniques. Optimization Study of the Stripline Resonator Technique for Dielectric Characterization Ahmed M. Further, reference plane resonance as described later can contribute to excessive ILD and the system should be checked to ensure that ILD is within bounds specified. Via stub h1 is the portion of the via from layer 3 to layer 1 and via stub h2 is the portion of the via from layer 3 down to layer 22. Jun 02, 2020 · Of course, the channel for Test Case #3 fails due to this 10dB of additional insertion loss. 9(a); C2 Stubs cause unwanted resonant frequency nulls which appear in the insertion loss plot of the channel. ) Mar 10, 2017 · For the example in Figure 1, the ¼ -wave resonant frequency of the long via stub is ~ 4. 28% at centre frequency 3. For example, the maximum stub length at 5GB/s should be less than 0. 7 mils for both channels. we would expect that the ratio of the stub resonant frequencies for both boards to be. observed that the second resonance is shifted towards left as the value of width changes with keeping first resonance unaltered. How to use a grid dip meter to measure resonance of an antenna: The resonant frequency of an antenna can be determined using a grid dip oscillator or dip meter by coupling the meter to the antenna and the searching for the lowest dip. )   simulation of trace and via structures will be demonstrated. Before doing this, we would like to give a qualitative estimation of the mode resonant behavior in the stub. Read more about measuring an antenna resonant frequency. edu, itoh@ee. The resonantly coupled structures can be driven by a single rf power system, through single rf drive loop, at a single rf frequency. 4 GHz) near the resonant frequency,. With a stub length of ~ 270 mils, this gives a Dkeff of 6. Therefore, every real capacitor behaves as a resonant circuit. In the last rule of thumb, we identified the frequency of the dip in the insertion loss from the quarter wave stub resonance. Also, the resonance occurs at low frequencies and open stubs are in this case. This therefore allowed the resonant frequency of the structure to be determined accurately with no loading effects from the feed. frequency band (Df) and resonant frequency(f) of each res-onator are listed in Table. Mar 08, 2017 · For the example in Figure 1, the ¼ -wave resonant frequency of the long via stub is ~ 4. In addition, the resonant frequency of both of these channels is almost the same at about 19 GHz. Use of WB-Extract and S2TDR with O-Wave allows The Antenna Calculator for Half-Wave Dipoles. The lon-ger the stub, the lower the resonant frequency is. 47% and a maximum transmission loss of −2. 27 dB, which depends on the curvature. 2 GHz resonance for a signal via with a 4 mm stub. This creates a second source of resonance as you now have incident and reflected waves interfering with each other in the via barrel. Especially via stubs lead to resonances that degrade the transmission. 6 shifts the resonant frequency higher, but at the expense of larger insertion loss (i. It is a good rule that the first resonant frequency should be equal to or greater than the seventh harmonic. NOVEL ZEROTH-ORDER RESONANCE IN COMPOSITE RIGHT/LEFT-HANDED TRANSMISSION LINE RESONATORS ATSUSHI SANADA, CHRISTOPHE CALOZ, and TATSUO ITOH Electrical Engineering Department, University of California, Los Angeles 405 Hilgard Ave. Note the fact that the resonant modes are strongly localized in the stubs. Note that graph line 112 in FIG. Proper use of plated through-hole vias in mmWave PCBs frequency—the quarter-wave reso-nant frequency—the round-trip delay from the active region of the via to the end of the stub and back equals a half-cycle. 2 in via) as a function of frequency. 2 Note that removing the via stubs (B1 – C1 and B2 – C2), using, for example, backdrilling, does not eliminate all resonant structures in this interconnect. If the signal has a significant  Via Stub Removed @ 10Gbps. 5 inches or 1. via stub resonance frequency