1971|12

5732

帖子

43

资源

版主

射频开关几个重要参数 [复制链接]

 

原文:

In the transmission path, RF Switches can efficiently convey paths.
Four basic electrical parameters can be used to describe the function of this sort of RF
switch. Despite the fact that numerous parameters affect the performance of RF switches,
the following four are crucial due to their significant correlation:
1. Isolation
Isolation is an index that measures the effectiveness of the RF switch cut-off by
attenuating the signal between the input and output of the circuit.
2. Insertion loss
When the RF switch is turned ON, insertion loss (also known as transmission loss)
is the total power loss. Because insertion loss can immediately contribute in system noise
figure, it is the most important metric for the RF designers.
3. Switching time
The time it takes for the RF switch to convert from ON state to the OFF state, and
vice versa is referred to as switching time. For high-power switching, this time can be
measured in microseconds, and for low-power high-speed switching, it can be measured
in nanoseconds. The most typical definition of switching time is the amount of time it takes
for the input control voltage to go from 50% to 90% of its ultimate power.
4. Power handling capacity
The power handling capability of a switch is defined as the maximum RF input
power that the switch can withstand without deteriorating its electrical performance
permanently.

译文:

在传输路径中,射频交换机可以有效地传输路径。四个基本电气参数可以用来描述这种射频开关的功能。尽管影响射频开关性能的参数很多,但以下四个参数由于具有显著的相关性而至关重要:

1。隔离隔离是通过衰减电路输入和输出之间的信号来衡量RF开关截止的有效性的指标。

2. 插入损耗当射频开关打开时,插入损耗(也称为传输损耗)是指总功率损耗。因为插入损耗会直接影响系统的噪声,所以它是射频设计人员最重要的指标。

3.开关时间RF开关从ON状态转换到OFF状态或从OFF状态转换到ON状态所需的时间称为开关时间。对于大功率开关,这个时间可以用微秒来测量,对于低功率高速开关,这个时间可以用纳秒来测量。最典型的开关时间定义是输入控制电压从其最终功率的50%上升到90%所需要的时间。

4. 功率处理能力开关的功率处理能力是指开关在不永久性降低电性能的情况下,所能承受的最大射频输入功率。

 

 

 

此帖出自RF/无线论坛
个人签名

射频【放大器】


回复

5732

帖子

43

资源

版主

机电RF开关首先在无线应用中使用的RF开关是机械开关(按键、天线开关和机电继电器)。那些机械或机电开关通常开关直流和低频,以及相对较高的电压和电流。它们需要有良好的电气接触,并使用高隔离材料。•有两种机电式射频开关:终端式和非终端式。

•当射频开关的所有端口端接50欧姆负载时,所选端口关闭,切断或隔离所有电流。入射信号能量将被终端电阻吸收,而不会以这种方式反射回射频源。

•在非端接RF开关中,系统必须完成外部阻抗匹配以减少能量反射。该无端接射频开关具有插入损耗低的优点。

•机电(EM) RF开关提供:-低插入损耗(<0.1dB) -高隔离(>100dB) -高功率处理-无视频泄漏-非常高的ESD抗扰度-其频率范围从直流启动-机电RF开关的工作寿命比固态开关低。

•机电开关的工作寿命可以定义为开关在满足所有射频和可重复性规格的情况下完成的周期数。

•工作寿命指的是开关的电气寿命和射频特性,而不是机械寿命(比电气寿命长得多)。有一些高质量的同轴继电器使用被称为“无摩擦开关”的机电开关(因为在跳线触点和中心导体之间没有产生摩擦),这种配置产生的开关可以机械驱动数千万次循环。缺点是,它们可能不会机械失效,但它们的插入损耗会因为触点电阻的时间增加而变得更高。

 

Electromechanical RF switches
First RF Switches that were used in wireless applications were mechanical
switches (keys, aerial switches, and electro-mechanical relays).
Those mechanical or electro-mechanical switches generally switch DC and low
frequencies, and relative high voltage and currents.
They require having good electrical contacts and to use high isolation materials.
• There are two types of electromechanical RF switches: terminated and non-
terminated.
• When all ports of an RF switch are terminated with a 50 ohms load, the selected
port is closed, cutting off or isolating all currents. The incident signal energy will be
absorbed by the termination resistor and will not be reflected back, to the RF source
in this way.
• In a non-terminated RF switch, the system must accomplish external impedance
matching to reduce energy reflection. The non-terminated RF switch has the
advantage of having a low insertion loss.
• Electro-mechanical (EM) RF switches provides:
- low insertion loss (<0.1dB)
- high isolation (>100dB)
- high power handling
- no video leakage
- very high ESD immunity
- their frequency range starts from DC
Electro-mechanical RF switches have lower operating lifetime than Solid-State switches.
• The operating life of an electro-mechanical switch can be defined as the number of
cycles the switch will complete while meeting all the RF and repeatability
specifications.
• The operating life refers to the electrical life and RF properties of the switch, and not
to the mechanical life (which is much longer than the electrical life).
There are some high-quality coaxial relays that use electro-mechanical switches referred
as“frictionless switching” (since there is no friction produced between the jumper contact
and center conductor), and this configuration produces switches that can mechanically
actuate for tens of millions of cycles.
The drawback is, they might not fail mechanical, but their insertion loss gets higher due to
increasing in time the resistance of the contacts.

个人签名

射频【放大器】


回复

5732

帖子

43

资源

版主

固态射频开关的类型和结构

There are few main types of Solid-State RF switches:
• High-Speed Silicon diodes RF switches
• PIN diodes RF switches
• Field Effect Transistors (FET) RF switches
• Hybrid (FET and PIN diode) RF switches
Two basic switch architectures that describe the behavior of the unused switch port are
classified as Absorptive or Reflective.
• Absorptive switches present a termination (most commonly 50Ω) to the unselected
arm typically at the expense of increased insertion loss.
Absorptive switch will have a good VSWR on each port regardless the switch mode.
• Reflective switches leave the unused port un-terminated.
In a reflective switch, the impedance of the port that is OFF will not be 50Ω and will
have a very high VSWR.
Reflective switches can be further categorized as: either reflective-open or
reflective-short.
- Reflective-open architectures do not have a shunt path to ground in the OFF
state; as a result, the loading on the unused port will be minimized.
For example, LNA bypass switches are reflective-open in order not to disturb the
LNA’s functionality when the switch is in the OFF state.
- Reflective-short architectures use a shunt path to ground.
This low impedance renders attached circuitry effectively useless.
• The rule is to use an absorptive switch when you need a good VSWR looking into
the port that is not switched to the common port, and to use a reflective switch when
high OFF port VSWR does not matter, and when the switch has some other desired
performance feature.
• In most cases, an absorptive switch can be used instead of a reflective, but not vice-
versa.

主要有几个类型的固态射频开关:

•高速硅二极管射频开关射频开关•

•PIN二极管场效应晶体管(FET)射频开关

•混合(场效应晶体管和PIN二极管)射频开关两种基本开关架构描述的行为未使用的交换机端口被归类为吸收或反射。

•吸收开关为未选择的臂提供一个终止(最常见的是50Ω),通常以增加插入损失为代价。无论交换机模式如何,吸收式交换机在每个端口上都有良好的驻波比。

•反射开关将未使用的端口未终止。在一个反射开关,端口的阻抗是OFF将不是50Ω,将有一个非常高的驻波比。反射开关可以进一步分类为:反射打开或反射短开关。

-反射式开放架构在OFF状态下没有到地的分流路径;因此,未使用端口上的装载将被最小化。例如,LNA旁路开关是反射开的,以便在开关处于OFF状态时不干扰LNA的功能。—短反射结构采用分流到地的路径。这种低阻抗使附着的电路有效地无用。

•规则是使用一个吸收开关,当你需要一个好的电压驻波比调查的端口不转向常见的端口,并使用反射关掉当高端口电压驻波比并不重要,当开关有一些其他的性能特性。

•在大多数情况下,吸收开关可以代替反射开关,但反之则不行。

个人签名

射频【放大器】


回复

5732

帖子

43

资源

版主

High-Speed Silicon diodes RF switches
• The silicon switching diode is the most basic function of almost every electronic
application.
• Switching diodes are also used in high-speed rectifying applications, such as in
radio receivers. Applications also include general-purpose switching and reverse
polarity protection in telecommunication industry.
• The low power (<100mW) high-speed silicon diode RF switches can provide
switching speeds down to 1ns, and ON resistances less than 0.5Ω.
• The DC current flow through the high-speed silicon diodes have to assure that they
are completely turned ON, because too little junction current cause them to conduct
partially resulting in high signal loss through the switch. Usually the DC bias current
for ON operation is about few mA and not exceeding 20mA.
• A single silicon switching diode can provide up to 20dB of isolation, and two back-
to-back silicon diodes can provide up to 30dB of isolation.

image.png  •硅开关二极管是几乎所有电子应用中最基本的功能。

•开关二极管也用于高速整流应用,如无线电接收机。应用领域还包括电信行业的通用开关和反极性保护。

•低功耗(<100mW)的高速硅二极管RF开关可以提供低至1ns的开关速度,并且ON电阻小于0.5Ω。直流电流流过高速硅二极管必须确保他们完全打开,因为太少的结电流导致他们传导部分导致高信号损失通过开关。通常ON操作的直流偏置电流约为少量mA,不超过20mA。

•单个硅开关二极管可以提供高达20dB的隔离,两个背对背硅二极管可以提供高达30dB的隔离。

个人签名

射频【放大器】


回复

5732

帖子

43

资源

版主

PIN diode RF switches

The PIN diode is constructed with a layer of intrinsic (undoped) semiconductor
material between very highly doped P type and N type material called P+ and N+.
This contrasts with a normal high-speed switching diode such as the common 1N914
which has a simple PN junction.

PIN二极管射频开关

PIN二极管是由非常高掺杂的P型和N型材料之间的一层本构(无掺杂)半导体材料构成的,称为P+和N+。这与普通的高速开关二极管形成对比,比如普通的1N914,它有一个简单的PN结。

 

image.png

An ordinary PN junction diode can be used to switch RF currents ON and OFF.  一个普通的PN结二极管可以用来开关RF电流的ON和OFF。

 

• In order to completely close OFF the current, the common diode must be reverse
biased with a voltage equal to the peak RF voltage to be blocked.

为了完全关闭电流,普通二极管必须反向偏置,其电压等于被阻断的峰值RF电压。

• For example, to block an RF signal of 10 V p-p, the diode anode must be 10 V DC
more negative than the cathode. If the diode is to remain turned ON for the
complete RF cycle, the DC bias current must exceed the RF current.
For example, if the diode is expected to pass 0.1 A of peak RF, it must have a
forward bias of at least 0.1 A DC.

。•例如,为了阻断10 V p-p的射频信号,二极管阳极必须比阴极更负10 V DC。如果二极管在整个射频循环中保持开状态,直流偏置电流必须超过射频电流。例如,如果二极管预期通过0.1 A的峰值RF,它必须具有至少0.1 A DC的前向偏置。

 

个人签名

射频【放大器】


回复

5732

帖子

43

资源

版主

PIN二极管的行为是明显不同的。由于本征层的存在,RF在P+和N+区域之间传输需要相当长的时间。延迟特性对于射频切换非常重要。

 

•PIN二极管对RF通常是关闭的,只需要一个偏置打开。如果一个射频周期的长度比这个延迟短,并且二极管不是正向偏置,电流流将是可以忽略的,二极管将会显示为OFF。

如果施加正向偏置电流,一些射频电流将流过,二极管开关将打开。

 

•在一个有限的范围内,二极管作为一个电流控制电阻射频。•电阻随着偏置电流的增加而减小。与固定电阻一起使用,PIN二极管可以用来构造一个电子控制的射频衰减器。

 

•二极管本身的电容和二极管封装将允许一些RF馈通电流在OFF条件下。在关断状态下,馈通总是大于零,因此,一个提供高隔离水平的开关通常会有两个PIN二极管元素。

个人签名

射频【放大器】


回复

5732

帖子

43

资源

版主

A series element (D1 in figure below) disconnects the switch from the source, and a shunt element (D2 in figure below) shorts out most of the feedthrough signal.

                                串联元件(图中D1)将开关与电源断开,并联元件(图中D2)使大部分馈通信号短路。

 

image.png

When the switch is ON, the series element will be biased ON and the shunt element will be unbiased and OFF. Conversely, when the switch is OFF, the series element will be unbiased and OFF and the shunt element will be biased ON to short out the feedthrough signal. However, a PIN diode is a semiconductor device that operates as a variable resistor at RF and microwave frequencies.

当开关处于ON状态时,串联元件将有偏置为ON,分流元件将无偏置为OFF。相反,当开关为OFF时,串联元件将无偏置为OFF,分流元件将偏置为ON,从而使馈通信号短路。然而,PIN二极管是一种半导体器件,在射频和微波频率下作为可变电阻工作。

 

• Its resistance value varies from less than 1Ω (ON-state) to more than 10 kΩ (OFFstate) depending on the amount of current flowing through it. As a current-controlled device, the resistance is determined only by the forward biased DC current. When the control current is switched ON and OFF, the PIN diode can be used for switching.

• Compared to high-speed silicon diode, an important feature of the PIN diode in switching applications is its ability to control large RF signals while using much smaller levels of DC excitation.

• The resistance of the PIN diode under forward bias is inversely proportional to the total forward bias current, making the PIN diode perfect for achieving excellent isolation at high frequencies.

 

•根据流过它的电流大小,其电阻值从小于1Ω (on -state)到大于10 kΩ (OFFstate)不等。作为一种电流控制装置,电阻仅由正向偏置的直流电流决定。当控制电流处于ON和OFF状态时,可以使用PIN二极管进行开关。

•与高速硅二极管相比,PIN二极管在开关应用中的一个重要特点是它能够控制大的射频信号,而使用更小的直流激励水平。

•PIN二极管在正向偏置下的电阻与总正向偏置电流成反比,使PIN二极管完美地实现了在高频率下优秀的隔离。

 

image.png

 

 

 

个人签名

射频【放大器】


回复

5732

帖子

43

资源

版主

PIN diode characteristics, such as: high switching speed, low package parasitic reactance and small physical size compared to a signal wavelength, make them ideal for use in broadband switch design.

PIN二极管的特点,如:高开关速度,低封装寄生电抗和小的物理尺寸比一个信号波长,使他们非常适合用于宽带开关设计。

• The drawback of PIN diodes is that they cannot be used at lower frequencies. One of the properties of the PIN diodes is the transit time frequency of the I-region defined as:

•PIN二极管的缺点是它们不能在较低的频率下使用。PIN二极管的特性之一是i区域的渡越时间频率定义为:

image.png

 其中W为i区宽度,单位为微米。

  • 如果频率高于ftransit, PIN二极管工作正常。
  •  在频率小于ftransit时,PIN二极管就像一个pn结二极管,并纠正RF信号,使得PIN二极管不适合在这些频率下使用。传输的频率通常在几kHz到1MHz之间。
  • 在反向偏置模式下,在较低的频率下,PIN二极管的电容特性类似于变容二极管。这种电容的变化和变化会影响PIN二极管作为开关在较低频率下的效用,就像在正向偏置模式下一样。

个人签名

射频【放大器】


回复

5732

帖子

43

资源

版主

PIN二极管通常用于设计控制射频信号路径的开关。串联型PIN电路中的衰减(隔离)随着PIN电阻通过增加正向电流而减小而减小。相反的情况发生在分流配置上。如果控制偏置在高和低(零)值之间快速切换,那么电路就像一个开关。

PIN diodes are often used to design a switch that controls the path of the RF signals. The attenuation (isolation) in the series type PIN circuit is decreased as the resistance of the PIN is reduced by increasing the forward current. The opposite occurs for the shunt configuration. If the control bias is switched rapidly between high and low (zero) values, then the circuit acts simply as a switch.

 

image.png

 

 •SPST(单极单掷)PIN二极管开关的隔离在10MHz时约为50dB,在1GHz时约为15dB。

•由于二极管上的偏压变化,负载电阻作为看到的源也变化;因此,隔离(衰减)主要是通过反射实现的,部分是通过PIN二极管的耗散实现的。

•在并联PIN二极管开关的上频率限制是由二极管寄生电容开始短路负载时插入损耗的增加决定的。然而,可以使用对称匹配电路,通过将二极管电容C合并到低通滤波器中来扩展这个频率限制。

• Isolation of a SPST (single-pole-single-throw) PIN diode switch is about 50dB at 10MHz and about 15dB at 1GHz.

• As the bias on the diode is varied, the load resistance as seen by the source also varies; consequently, the isolation (attenuation) is achieved primarily by reflection and partly by dissipation in the PIN diode.

• The upper frequency limitation in a shunt PIN diode switch is determined by the increase in insertion loss as the diode parasitic capacitance starts to short out the load. However, can be used a symmetrical matching circuit that extends this frequency limitation by incorporating the diode capacitance C, into a low pass filter.

 

image.png

选用电感值L,构成切比雪夫等纹波滤波器。

通过反向偏置降低二极管电容C,

可以获得更高的高频或更低的纹波。

The inductance value L, is chosen to form a Chebyshev equal ripple filter. The upper frequency is determined by the diode capacitance C, by ripple value, and by R.

• Higher upper frequencies or lower ripple may be obtained by lowering the diode capacitance C using reverse bias.

 

Depending on the performance requirements, the switch can consist of all series diodes, all shunt diodes, or a combination of series and shunt diodes.

根据性能要求,开关可以由所有串联二极管、所有分流二极管或串联和分流二极管的组合组成。

image.png

  •  • Series PIN diode switches are capable of functioning within a wide bandwidth, which is limited by the biasing inductors and DC blocking capacitors. In reverse biased mode the parasitic capacitance of PIN diodes gives rise to poor isolation at microwave frequencies, with a 6dB per octave roll-off versus frequency. In some applications these parasitic elements can be either“tuned-out” by additional external reactance (parallel inductor) which actually is utilized by forming a resonant circuit around the diode. The bandwidth of such structures is, however, limited.
  • •系列PIN二极管开关能够在宽带宽内工作,这是受偏置电感和直流阻塞电容的限制。在反向偏置模式下,PIN二极管的寄生电容导致了在微波频率下较差的隔离,每倍频滚转的频率为6dB。在一些应用中,这些寄生元件可以通过额外的外部电抗(并联电感)“调谐”,实际上是通过在二极管周围形成一个谐振电路来利用的。然而,这种结构的带宽是有限的。
  • • Shunt PIN diode switches feature high isolation relatively independent of frequency. To turn a switch on, PIN diodes are reversed, and this means a dominant reverse biased capacitance exists. Commonly, designers use a circuit transmission line to create series lumped inductance to achieve a low pass filter effect which enables the switch to work up to the desired frequency. Shunt diodes RF switches have limited frequency bandwidth, arising from the use of theλ/4 transmission lines between the common junction and each shunt diode. At frequency fo, where the transmission lines areλ/4 in length, when diode D1 is forward biased and diode D2 is reverse biased, the RF signal flows from port 3 to port 2, and the RF port 1 will be isolated. Theλ/4 line will transform the short circuit at D1 into an open circuit at the common junction, eliminating any reactive loading at that point. As the frequency is changed from fo, the transmission lines will change in electrical length, creating a mismatch at the common junction.
  • •分流PIN二极管开关具有高隔离相对独立于频率。打开一个开关,PIN二极管是反向的,这意味着一个主要的反向偏置电容存在。通常,设计人员使用电路传输线来创建串联集总电感,以实现低通滤波器效果,使开关工作到所需的频率。分流二极管射频开关有有限的频率带宽,由使用λ/4传输线之间的公共结和每个分流二极管。在频率为λ/4的情况下,当二极管D1正向偏置,二极管D2反向偏置时,RF信号从端口3流到端口2,RF端口1被隔离。λ/4线将在D1处的短路转变为在公共结处的开路,消除在那一点上的任何无功负载。当频率从fo改变时,传输线的电气长度将发生变化,在公共结处产生不匹配。
  • There are PIN switch designs that use combination of series and shunt diodes (compound switches), and switches that use resonant structures (tuned switches) to improve isolation and insertion loss performance. These switches are more complicated to design and consume higher biasing current compared to series or shunt PIN diode switches.
  • 有一些PIN开关设计使用串联和分流二极管的组合(复合开关),以及使用谐振结构的开关(调谐开关),以提高隔离和插入损耗性能。与串联或并联PIN二极管开关相比,这些开关设计更复杂,消耗的偏置电流更高。
  • image.png

In a PIN diode RF switch design, the biasing path is connected to the RF path of the switch and DC blocking capacitors are needed at the RF ports.

 在PIN二极管RF开关设计中,偏置路径连接到开关的RF路径,RF端口需要直流隔离电容。

  • The DC blocking capacitors will degrade the insertion loss performance of the PIN diode switch:
  • 直流阻塞电容器会降低PIN二极管开关的插入损耗性能:
  • at low frequencies due to the high pass filter effect of the capacitor.
  • 在低频时,由于电容器的高通滤波效应。

  • at high frequencies due to SRF (self-resonant frequency), and due to transmission loss through the capacitor.
  • 在高频率下,由于SRF(自谐振频率),以及由于通过电容器的传输损耗。

RF chokes (inductors) are used along the biasing paths to avoid RF signal leakage.

射频扼流圈(电感)沿偏置路径使用,以避免射频信号泄漏。

  • The RF choke must have high impedance at low frequencies so that the RF signal will not leak through the biasing path leading to higher insertion loss. A good rule is the reactance XL of the inductor at working frequency should be at least ten times higher than port impedance. If port impedance is 50Ω the XL > 500Ω At the same time, the RF choke should have a high SRF (self-resonant frequency) to enable broadband switch design.
  • 射频扼流圈在低频时必须具有高阻抗,这样射频信号才不会通过偏置路径泄漏而导致更高的插入损耗。一个好的规则是电感器在工作频率下的电抗XL应该至少比端口阻抗高10倍。如果端口阻抗为50Ω XL > 500Ω同时,RF扼流圈应具有高SRF(自谐振频率),以实现宽带开关设计。

个人签名

射频【放大器】


回复

5732

帖子

43

资源

版主

场效应晶体管的开关

场效应晶体管(FET)是一种半导体器件,它依靠一个电场来控制半导体材料中通道的电导率。

  • 源极和漏极之间的电流是由栅极和源极之间施加的电压控制的。
  • 由于对漏源极电阻(RDS)的良好控制,FET开关是稳定和可重复的。

  • 在栅极和源极之间施加反向偏置电压会导致该结的损耗区域扩大,从而“掐断”源极和漏极之间的通道,控制电流通过该通道传播。

  • 在OFF状态下,导通通道被耗尽(掐断),这导致FET表现出非常高的电阻(ROFF),这一机制在低频下提供了良好的隔离。

  • 场效应晶体管基本上是一个栅压控制电阻。插入损耗很大程度上取决于通道电阻,栅源电容决定隔离。为了增加隔离(高阻抗OFF状态),在源极和漏极之间连接一段短(感应)传输线,以谐振出夹断电容Coff。

 

 

image.png

 用于ON和OFF场效应管的理想等效电路

电感器L是传输线的一小段,用于并联谐振RC组合,以增强高阻抗状态。电阻Rs是掐断时的总串联电阻(未耗尽的通道电阻加上源极和漏极接触电阻)。高品质(Q)需要小Ron, r和Coff。一个很好的近似是:

 

 

image.png

缩放栅极宽度允许在隔离和插入损耗之间进行权衡。如果栅格宽度加倍,Ron和Rs减半,Coff加倍,Q不变。10 GHz和30 GHz的典型Q2值分别约为1000和100。在正常运行中,漏极没有偏压。栅上的负偏置(相对于源)将通道夹断。零或正栅偏置打开通道。

  • 由于漏源极电容(CDS)的影响,FET开关的隔离性能在较高频率时降低。

例如,GaAs场效应晶体管的CDS电抗XC为10GHz,约为320Ω,可以提供约10dB的漏源-漏源隔离,这不足以满足隔离性能。

使用FET的单极双掷SPDT开关的简化示意图如下:

 

image.png

 为了将RF从公共端口切换到端口2,Q1和Q4被反向偏置,使源极和漏极之间的通道被掐断;Q2和Q3正向偏置,使得漏极和源极之间存在较低的通道电阻。

Q1和Q3作为串联器件,用于开关RF ON和OFF,而为了更好的隔离,

Q3和Q4用于将泄漏到OFF端口的RF分流到地。

  •  为了提高一个场效应管开关的隔离度和线性度,可以在每个臂上串联增加更多的场效应管。OFF状态下的功率处理可以通过串联“堆叠”fet来增加。如果处理得当,射频电压将在栅极之间分配。因此,具有12伏击穿的双层fet可以实现与具有24伏击穿的PIN二极管开关相当的功率处理。
  • 对于堆叠型场效应管开关,理想情况下功率处理随堆叠中场效应管数量的平方而增加。双层结构(两个FET串联)的功率处理是单一FET结构的四倍。相邻栅极之间需要充分的隔离,以使电压均分。电阻栅极馈电是实现这一目的的一种方法。 image.png
  •  在上述的场效应管开关中,如果在每个场效应管上增加漏源极旁路电阻(few kΩ),可以提高整体插入损耗和开关的线性度。
  • 为了改善OFF状态下的功率处理,堆叠fet的一个缺点是ON状态下的串联电阻(插入损耗)被乘起来。

在FET型开关设计中,偏置路径(V控制)没有连接到开关的RF路径,就像在PIN开关的情况下一样。这为FET开关提供了一个更简单的直流偏置路径,消除了对昂贵的高性能RF扼流圈的需求,避免了由于偏置路径连接到RF路径而导致的插入损失,就像PIN二极管开关一样。

  • FET的ON电阻通常高于PIN二极管,导致FET开关的插入损耗性能低于PIN二极管开关。

  • 作为电压控制器件,FET开关比PIN二极管开关消耗更少的电流。

个人签名

射频【放大器】


回复

3316

帖子

0

资源

纯净的硅(高级)

好大的工作量啊,谢谢分享,学习学习。


回复

87

帖子

17

资源

一粒金砂(中级)

这工作量太猛了。。。开关东西不好找,谢谢分享,我们好好学学

点评

很多东西是需要反复看 多交流才能搞明白的   射频微波这个东西涵盖面太广   所以需要不断探索求知。。  详情 回复 发表于 2022-4-18 20:54

回复

5732

帖子

43

资源

版主

hellomankind 发表于 2022-4-18 18:46 这工作量太猛了。。。开关东西不好找,谢谢分享,我们好好学学

很多东西是需要反复看 多交流才能搞明白的   射频微波这个东西涵盖面太广   所以需要不断探索求知。。

个人签名

射频【放大器】


回复
您需要登录后才可以回帖 登录 | 注册

相关帖子
查找数据手册?

EEWorld Datasheet 技术支持

相关文章 更多>>
    关闭
    站长推荐上一条 1/7 下一条

    About Us 关于我们 客户服务 联系方式 器件索引 网站地图 最新更新 手机版

    站点相关: 安防电子 汽车电子 手机便携 工业控制 家用电子 医疗电子 测试测量 网络通信 物联网

    北京市海淀区知春路23号集成电路设计园量子银座1305 电话:(010)82350740 邮编:100191

    电子工程世界版权所有 京B2-20211791 京ICP备10001474号-1 电信业务审批[2006]字第258号函 京公网安备 11010802033920号 Copyright © 2005-2022 EEWORLD.com.cn, Inc. All rights reserved
    快速回复 返回顶部 返回列表