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# Lambda Effect

61 Threads found on edaboard.com: Lambda Effect

## the effect of the roughness to the spread of the microwave?

It's not easy to understand what you want say. Is the Shielded structure a waveguide, or a mirror or what? generally speaking the roughness play a role smaller that many people thinks. For a Waveguide the roughness increase lhe loss (not so mutch as you change the metal from Ag to Al). For a mirror a gaussian distributed roughness generate an ef

## Why I can't see the effect of W/L on Ids

Hi: According to the equation of Ids=1/2K'W/L(Vgs-Vt) (in saturation), the Ids should increase with the ration of W/L. When I use Pspice to do the simulation, I can't observe the increase in Ids in the saturation region. I am using Level 1 model, and the parameter is : VTO=1.4 KP=0.05e-3 lambda=0.05 and I set the width W as the parameter

## Which factors will effect communication distance ?

According to the free space path loss formula: Ploss = 20*log((4*Pi*d)/lambda) where: d = distance in meters lambda = wavelength in meters Pi = 3.14 That means at 315 MHz the path loss at 100m is 62dB. Assuming a 0dBd antenna gain on both sides, and ignoring other loss factors and interferers, your link budget should be ok for a pro

## Sizing of Transistor in Analog Layout

Long channels especially used in current mirrors to reduce lambda effect . As lambda inversely proportional to L .Large area less is the mismatch. Addressing skyismylimit question :I think Gate resistance would be the major factor considered while doing layout for large transistor .

## Simulation with and without body effect.

Deae pipeline, u are talking of lambda, the channel length modulation parameter if i am not mistaken. Hspice gives "gds" for MOS and inverse of that is R. But lambda should be provided by the foundry, if they donot provide it, then we need to chracterise our mos. The process is given in appendix in Allen holberg.

## how to confirm the L of MOS in analog circuir?

Hi, The sizing of L is depend on type of application when u design a circuit. Mostly in the high frequency signal path, the size of L is to keep the min as in the design manual, in order to avoid parasitics cap which will degrade bandwidth. Like in the the design of differential amplifier, the L size of the tail transistor will be kept 2 or 3 ti

## Ron in Saturation region

Hi Surianova, As you said, in saturation region current , Ids will be constant for even Vds change, but since the existence of short channel effect/lambda effect, anyhow you won't flat curve. So, the value of Ron could be measureable as I stated. Other's opinion are welcome. Correct me if im wrong. Thanks Surianova. The slope which (...)

## questions about OP design procedure in TSMC018 technology

usually i define the ICMR and the output output rail-to-rail voltages and use this specifications in helping me calculate my Vdsat/Vov. the hand calculation should give a close match to the simulator, recheck your calculations especially the lambda effect on L

## PCB electrical length, effect on RF performance

In simple words, In a transmission line applied with 1G Hz sinusoidal frequency all the points along the line will not have same potential. They behave same as sinusoidal and repeat the same after some point of distance. The minimum distance at which they posses is depend on the dielectric constant i mean it is related to lambda. Means after

## Air box size effect on the results in HFSS

abhishekabs - im not familiar with that software - but i would suggest yes, in general the larger the box typically larger or equal to lambda/4 the greater accuracy you will get in radiation pattern data

## BSIM3 and lambda parameter

How do I get the value of \lambda ( the channel length modulation parameter for MOSFETs), starting from a BSIM3 model? And what about N_A, N_D (acceptors and donors concentrations) and the \gamma coefficient for the body effect? Is there a web reference with all of the BSIM3 parameters described? Thank

## Nonlinear (Kerr effect) FDTD soliton simulation

Hey, I'm trying to simulate a light soliton using FDTD with Mur's boandary conditions. The results don't explode but I get funny solutions (Sometimes the soliton loses amplitude, sometimes it gains amplitude...) that change when I choose different resolutions for the simulation that should all be small enough for this sort of simulati

## Help: Effect of Proximity to 3G Ants Performance

I have two 3G ceramic antennas operating in 850, 1900, and 2100 MHz band that are mounted in vertical and horizontal plane to compensate polarization diversity. Two antennas are 10 mm apart. I heard that when antennas stay closer than lambda/2, there will be a coupling effect deducts antenna performance. But how does the coupling effect (...)

## Voltage Dependent LAMBDA in SPICE.

Hi, For the SPICE model of MOSFET, How can I define the lambda as a gate voltage dependent parameter? Thank you so much, I am using both PSPICE and NGSPICE. Best, KUI

## How does these effect the performance of short channel and long channel?

the channel length modulation, which is valid also for long channels, is very relevant in short channel MOSTs. In the simple parabolic equation, the lambda coefficient is inversely proportional to L, so for very short transistors the drain current increment with Vds is decisively relevant. Body effect is not a phenomena involved only in short, but

## channel length modulation effect on the digital circuit

Hello the channel length modulation or lambda has a huge effect on the analog circuit, therefor the analog circuit can not not apply the smallest channel length available by the modern technology . digital circuit in the othe rhand working in the linear and cutoff region that is not effected by lambda as I believe. so (...)

## lambda/12 Transmission line at higher frequencies

Hi, Can I use lamda/12 length transmission line while designing matching circuits for high frequencies. When I calculate the length of transmission line using c/f I get 49mm. Can I use 5mm 0r 4mm transmission line. Regards, Praveen

## Can i replace short-circuited stub L with open-circuited L+lambda/4?

For a single frequency circuit, yes you can. The added lambda/4 (open end) behaves as a short circuit, so you can replace a short circuit for an open stub. You may experience some reduction in Q factor as the short circuit will not be zero Ohms (due to transmission line loss). you should check your new solution over the full frequency range as

## Which antenna is insensitive to the effects of a wall?

You can use a 'standard' lambda/4 antenna and place it lambda/4 away from your metalic wall. So your wall will serve as a reflector and give you an additional gain. Bye

## PML on HFSSv9.1 and the Minimum Radiatin Distance Parameter

Hello everyone, when assigning a PML on a DUT(the PML must be assigned on an AirBox which surrounds the DUT,with a thickness of lambda/4 at least!)a dialog window appear and a Minimum Radiating Distance is calculated. I don't known exactly the effect of the variation of this parameter. I see that if i use the default value (82mm for example) i ge

## Help me understand the calculation of W/L ratio in analog

Srivats.. ...please remember following 2 rules for current mirrors.. 1. always use Channel length which is 4-5 * Lmin ...(though this is ideal for DSM i.e < 0.25u)....the best thing wud be for u to characterize the MOS and see for which 'L' Id slope is less...use that length 2. Ensure that Vds of mirror X'tors are similar..this takes out (1+

## channel length modulation

1) plot of o/p resistance vs Vds for different values of Vgs 2) o/p characteristics 3) lambda in zoomed in view all for a 0.18um process

## Experience with planar antennas in MWO

The height of top layer should be much more, than lambda (mean for microstrip structure) for boundary effect (with open =377) avoidence

## Why Vth changes with transistor size and bias condition

vt is a parameter of channel lenght in both pmos and nmos. this effect is called channel modulation effect considered with parameter lambda in the equation of cmos current equation. the best way to bypass this altering effect is to connect source to bulk of the mosfet. I think what you said should be body (...)

## How to calculate the path loss when measuring air sensitivity inside

Free space path loss formula: Ploss = 20*log((4*Pi*d)/lambda) where: d = distance in meters lambda = wavelength in meters Pi = 3.14

## Question about waveport in HFSS

Deal all, I am simulating a filter with 50Ω microstrip as input/ouput (Er=2.2, h=1mm,w=3.11mm, Fre=9-11GHz) in HFSS. According to the rules, the width of waveport is about 5w and the height of waveport is about 4h. However, the dimensions of the waveport exceed the lambda/2, which permits the TE10 retangtular waveguide mode excitation. If t

## What's the purpose of shorting radiator to ground for PIFA ?

hi, the shorting pin or wall in a MSA, that converts it into a PIFA, is for making it suitable for use at lower freq. operations.suppose a Microstrip patch of resonant length L (approx= lambda/2 length) is shorted at the corner with a shorting pin,then the resonant length (quarter-wavelength)will be along half the perimeter of the patch,i mean l

## PCLM parameter in BSIM3.2 model

Hi, I have a question on the chanel length modulation parameter, i.e., PCLM. Can anyone pls. tell me if this parameter is the lambda in the drain current equation to account for the channel length modulation effect? I have this question is because I set pclm equal and not equal zero, I found not much drain current descrepancy for a current mirr

## Microstrip antenna array

You have to define a lot of requirements before select the inter-elements spaicng, at least: - peak gain - beamwidth (in both planes) - radiator element size and coupling - bandwidth the grating lobes are not a concern if you don't have to scan the beam away the boresight direction, unless you have an inter-element spacing > 0.9/1.0 lambda

## What is the advantage of submicron over normal technology?

Submicron technology is a technology for smaller lambda like 0.25micron nad below like 0.18micron, some even consider 0.5 micron is submicron technology... But when it goes as 90nano and below it's consider as sub deep micron @ nanotachnology. well for a same parameter, same technolgy...the usual different between them is at the physical char

## influence of CPW substrate thickness on CPW loss

I am little bit confused about the influence of CPW substrate thickness h on line loss. I read from some paper that say the h should be larger thant W+2S to reduce the interactive between surface wave mode and CPW mode. But on the other hand the h should be smaller than the 0.1 lambda (in substrate) to increase the cut-off frequency of surface wa

## input impedance of CPW fed slot antenna in CST

1) how to determine the input impedance of CPW and slot antenna separately in CPW fed slot antenna structure 2) what should be the length of CPW, so that i should only get the impedance of slot in CPW fed slot antenna structure..... ?? Should it be be lambda/2, coz it will not effect the impedance of load ( slot antenna) ???

It is called channel-length Modulatioon effect, dependented on L of device, and have a factor named lambda which having value of (0.005~0.03) in general.

## How can I connect 4 antennas to 1 receiver?

hay man, just look at minicircuits, or k&l, or any other RF componnets comp. buy a 4->1 RF combiner (splliter), it will most of the time be phased macth, then just use equal length cables and connect the 4 antennas to the splitter, if the phase match isn't 100% than you'l have a tillted beem, so just have to move the array to the other direct

## Questions about SAW filter design

hey all, i'm working on the design of a 35-45 MHz SAW filter on a 500mm, 36degrees Y-cut, lithium niobate substrate. Q1) Is it important how do i place the fingers on the substrate? I mean, does the direction on the substrate differ? Q2) I have some idea about the x-axis which is finger width (lambda/4) and finger length (lambda) how about th

## need help with small signal gain

At first, if lambda is zero there is no channel length modulation effect, ro will be zero for all cases. Besides, gamma is zero, there is no body effect, gmb are all gone. It looks like Common Source degerenation case. Gain ~ -gm1*Rd/(1+gm1*Rs)~-gm1*Rd/(1+gm1*1/gm2)

## Question about TRL standards for calibration

If I well remember (I made it few years ago): Thru is zero length (although it is non zero) so no special requirements Reflect is better to do with a short, for the reason you mention using an open. Line should be lambda/4 in the middle of your frequency range, and you have to use (theorically) a different line for each octave you need to includ

## Some problems with the wilkinson power divider

The resistor helps in isolation of the ports. but the BAD return loss of the Difference ports(s22,s33) is due to impedance mismatch at those ports. you should try to tune the length of the lambda/4 section to get an optimum response.

## How can we calculate the distances between antennas?

well ur question is a bit hard to answer, we dont know either ur are taking about elements of same type or any other antenna is the enviroment anyways first thing u must consider its spacing, the spacing between to antenna is very important as u increase spacing so does the beamwidth of main lobe decreased and also effect the minor lobes which g

## maximun gain achievable with dipole

i am modeling a half wavelength dipole parallel to ground plane in cst . i want to see the effect on the performance of dipole with changing the height of the dipole above the ground plane. when i look at the farfield pattern it is showing the gain apprx 8db which i cant explain. the gain of dipole in free space is approx 2.14 dbi. so when we u

## CMOS ???? CMOS PARASITICS ?

what are CMOS parasitics ? what is lambda parameter ? give examples thanks in advance

## Basic question in analog design

1- like your answer, this make the lambda of the mos low 2.-different (w/l) mos device used in analog and digital circuit showes the different application of analog and digital circuit

## EBG structures and number of cells

hello shahid.. as a thumb of rule always make the total size of your EBG ground plane greater than 1.1 lambda. As we determine the reflection phase of EBG unit cell considering it as infinite, more the number of cells, closer it will give results to simulated one. I've tried to go below 1.1 lambda but results then started changing. So keep the EBG

lambda = 1/L * d(Xd)/d(VDS) so a bigger L => a smaller lambda, which means less channel length modulation effect. ro = 1/(lambda*ID) so a bigger L also means a bigger small signal output resistance. As far as matching goes, you want the transistor sizing to be as large as possible. Equation 13.62 in Razavi indicates: (...)

## A question about a differential amplifier design.

Hello, using the follow spice netlist, V(6) = 0V when VID = 0V. But, what if I want V(6) = 1V when VID =0V. Which parameters should be adjusted? I changed VIC, but this seems have no effect. Thanks * *.lib 'E:\software\asmc\models\IC5.1.41\hspice\bc35hv_mod_hspice.lib' MOS_TT * VID 7 0 DC 0V AC 1V E+ 1 10 7 0 0.5 E- 2 10 7 0 -0.5 VIC 1

## HFSS - Antenna directivity with infinite ground plane

Hi guys, I'm using HFSS to simulate an antenna, and I've run into an interesting problem. The antenna is surrounded by a standard airbox, lambda/8 at the longest wavelength away from the antenna, as recommended. I'm interested in simulating the effect of an infinite ground plane on the antenna, so I use a perfect E boundary on the bottom fac

## why farfield pattern has more ripple

This likely has nothing to do with single element side lobes as are alluded to in above post. The relevant section in my link above is: "For discrete aperture antennas (such as phased arrays) in which the element spacing is much greater than a half wavelength, the aliasing effect causes some sidelobes to become

## Folded Dipole Antenna

HI Frankie To answer your questions. Beginning with yagi uda 1.you know its simply bunch of dipoles arranged on a boom with a certain distance between each other.main elements in the yagi uda antenna is driven element(main element) reflector and directors. Driven element is the dipole connected directly to the supply reflector and director ele

## Power absorbed by fractals

I define 2 wave ports (each port is far from structure face by 2*lambda) and the boundary is PML (far from structure face by lambda/4). I don't think you should define ports far from the structure. One port touch the front face of the structure, and the other port touch the back face.

## 3x3 mimo directional antenna

hi 1-for array antenna CST software is working better than other software 2- u can design a common patch antenna for this 3 -distance between antenna can be between lambda/4 to lambda/2