Several important parameters of RF switches

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Several important parameters of RF switches [Copy link]

 

original:

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.

Translation:

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. Isolation Isolation is a measure of the effectiveness of an RF switch cutoff by attenuating the signal between the circuit input and output.

2. Insertion loss Insertion loss (also called transmission loss) refers to the total power loss when the RF switch is turned on. Because insertion loss directly affects the noise of the system, it is the most important indicator for RF designers.

3. Switching time The time required for an RF switch to switch from the ON state to the OFF state or from the OFF state to the ON state is called the switching time. For high-power switches, this time can be measured in microseconds, and for low-power high-speed switches, this time can be measured in nanoseconds. The most typical definition of switching time is the time required for the input control voltage to rise from 50% to 90% of its final power.

4. Power handling capability The power handling capability of a switch refers to the maximum RF input power that the switch can withstand without permanently degrading its electrical performance.

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Electromechanical RF Switches The first RF switches used in wireless applications were mechanical switches (buttons, antenna switches, and electromechanical relays). Those mechanical or electromechanical switches usually switch DC and low frequencies, as well as relatively high voltages and currents. They need to have good electrical contact and use high isolation materials. There are two types of electromechanical RF switches: terminated and unterminated.

When all ports of the RF switch are terminated with a 50 ohm load, the selected port is closed, cutting off or isolating all current. The incident signal energy will be absorbed by the terminal resistor and will not be reflected back to the RF source in this way.

In a non-terminated RF switch, the system must complete external impedance matching to reduce energy reflection. This non-terminated RF switch has the advantage of low insertion loss.

Electromechanical (EM) RF switches offer: - Low insertion loss (<0.1dB) - High isolation (>100dB) - High power handling - No video leakage - Very high ESD immunity - Its frequency range starts from DC - The operating life of electromechanical RF switches is lower than that of solid-state switches.

The operating life of an electromechanical switch can be defined as the number of cycles the switch completes while meeting all RF and repeatability specifications.

Operating life refers to the electrical life and RF characteristics of the switch, not the mechanical life (which is much longer than the electrical life). There are some high-quality coaxial relays that use an electromechanical switch called a "frictionless switch" (because no friction is created between the jumper contacts and the center conductor), and this configuration produces a switch that can be mechanically actuated for tens of millions of cycles. The disadvantage is that they may not fail mechanically, but their insertion loss will be higher due to the increase in contact resistance over time.

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.

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Types and Constructions of Solid-State RF Switches

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.

There are several main types of solid-state RF switches:

High-speed silicon diode RF switch RF switch

PIN diode field effect transistor (FET) RF switch

Hybrid (FET and PIN diode) RF switches Two basic switch architectures describe the behavior of unused switch ports as either absorptive or reflective.

Absorptive switches provide a termination (most commonly 50Ω) to the unselected arm, usually at the expense of increased insertion loss. Absorptive switches have good VSWR on each port, regardless of switch mode.

Reflective switches leave unused ports unterminated. 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 classified as: reflective open or reflective short switches.

-The reflective open architecture has no shunt path to ground in the OFF state; therefore, loading on unused ports will be minimized. For example, the LNA bypass switch is reflective open so as not to interfere with the function of the LNA when the switch is in the OFF state. —The short reflective structure adopts a shunt path to ground. This low impedance makes the attached circuit effectively useless.

The rule is to use an absorptive switch when you need a good VSWR as the port under investigation is not turned to the common port, and use a reflective switch when a high port VSWR is not important and when the switch has some other performance characteristics.

In most cases, an absorptive switch can replace a reflective switch, but not vice versa.

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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.

Silicon switching diodes are the most basic functions in almost all electronic applications.

Switching diodes are also used in high-speed rectification applications such as radio receivers. Applications also include general purpose switching and reverse polarity protection in the telecommunications industry.

Low power (<100mW) high speed silicon diode RF switches can provide switching speeds as low as 1ns and have an ON resistance of less than 0.5Ω. DC current flowing through high speed silicon diodes must ensure that they are fully turned on, as too little junction current causes them to conduct partially resulting in high signal losses through the switch. Typically the DC bias current for ON operation is about a small number of mA, no more than 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.

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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 Diode RF Switch

PIN diodes are made of a layer of constitutive (undoped) semiconductor material between very highly doped P-type and N-type materials, called P+ and N+. This is in contrast to ordinary high-speed switching diodes, such as the common 1N914, which have a simple PN junction.

An ordinary PN junction diode can be used to switch RF currents ON and OFF. An ordinary PN junction diode can be used to switch RF currents ON and 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.

To completely shut off the current, a normal diode must be reverse biased with a voltage equal to the peak RF voltage to be blocked.

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.

For example, to block a 10 V pp RF signal, the diode anode must be 10 V DC more negative than the cathode. If the diode is to remain on for the entire 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.

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The behavior of a PIN diode is significantly different. Due to the presence of the intrinsic layer, it takes considerable time for the RF to propagate between the P+ and N+ regions. The delay characteristic is very important for RF switching.

PIN diodes are normally OFF to RF and only require a bias to turn on. If the length of an RF cycle is shorter than this delay, and the diode is not forward biased, current flow will be negligible and the diode will appear OFF.

If a forward bias current is applied, some RF current will flow and the diode switch will open.

Over a limited range, the diode acts as a current-controlled resistor at RF. The resistance decreases as the bias current increases. Used with a fixed resistor, a PIN diode can be used to construct an electronically controlled RF attenuator.

The capacitance of the diode itself and the diode package will allow some RF feedthrough current in the OFF condition. In the OFF state, the feedthrough is always greater than zero, so a switch that provides a high level of isolation will usually have two PIN diode elements.

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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.

The series element (D1 in the figure) disconnects the switch from the power supply, and the shunt element (D2 in the figure) shorts out most of the feedthrough signal.

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.

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

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.

Its resistance 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. A PIN diode can be used to switch when controlling the current in the ON and OFF states.

An important feature of the PIN diode in switching applications is its ability to control large RF signals using smaller DC excitation levels compared to high-speed silicon diodes.

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

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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.

Characteristics of PIN diodes, such as high switching speed, low package parasitic reactance and small physical size compared to a signal wavelength, make them very suitable for broadband switch designs.

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:

The disadvantage of PIN diodes is that they cannot be used at lower frequencies. One of the properties of a PIN diode is that the transit time frequency of the i region is defined as:

Where W is the width of zone i, in micrometers.

• If the frequency is higher than ftransit, the PIN diode works normally.
• At frequencies less than ftransit, the PIN diode behaves like a pn junction diode and corrects the RF signal, making the PIN diode unsuitable for use at these frequencies. The frequencies of transmission are typically between a few kHz and 1 MHz.

• In reverse bias mode, at lower frequencies, the capacitance characteristics of a PIN diode are similar to those of a varactor diode. This change and variation in capacitance affects the effectiveness of the PIN diode as a switch at lower frequencies, just as it does in forward bias mode.

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PIN diodes are often used to design switches that control the path of RF signals. Attenuation (isolation) in a series-type PIN circuit decreases as the PIN resistance decreases by increasing the forward current. The opposite occurs with a shunt configuration. If the control bias is quickly switched between high and low (zero) values, the circuit behaves like a switch.

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.

The isolation of the SPST (single-pole, single-throw) PIN diode switch is approximately 50dB at 10MHz and approximately 15dB at 1GHz.

As the bias voltage on the diode changes, the load resistance seen by the source also changes; therefore, isolation (attenuation) is achieved primarily through reflection and partially through dissipation in the PIN diode.

The upper frequency limit of a parallel PIN diode switch is determined by the increase in insertion loss as the diode parasitic capacitance begins to short-circuit the load. However, this frequency limit can be extended by incorporating the diode capacitance, C, into the low-pass filter using a symmetrical matching circuit.

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.

The inductance value L is selected to form a Chebyshev isoripple filter.

By reverse biasing the diode, the capacitance C is reduced.

Higher high frequencies or lower ripple can be obtained.

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.

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

• 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.
• Series PIN diode switches are capable of operating over a wide bandwidth, which is limited by the bias inductance and DC blocking capacitance. In reverse bias mode, the parasitic capacitance of the PIN diode results in poor isolation at microwave frequencies, with a 6dB roll-off per octave. In some applications, these parasitic elements can be "tuned" with additional external reactance (shunt inductance), in effect exploiting the fact that a resonant circuit is formed around the diode. However, the bandwidth of this structure is limited.
• 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.
• Shunt PIN diode switches have high isolation that is relatively independent of frequency. To open a switch, the PIN diode is reversed, which means a major reverse biased capacitor is present. Typically, designers use circuit transmission lines to create a series lumped inductor to achieve a low pass filter effect to enable the switch to operate to the desired frequency. Shunt diode RF switches have limited frequency bandwidth, which is achieved by using a λ/4 transmission line between the common junction and each shunt diode. At a frequency of λ/4, when diode D1 is forward biased and diode D2 is reverse biased, the RF signal flows from port 3 to port 2, and RF port 1 is isolated. The λ/4 line turns the short circuit at D1 into an open circuit at the common junction, eliminating any reactive load at that point. As the frequency changes from fo, the electrical length of the transmission line will change, creating a mismatch at the common junction.
• 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.
• There are some PIN switch designs that use a combination of series and shunt diodes (compound switches), as well as switches that use resonant structures (tuned switches) to improve isolation and insertion loss performance. These switch designs are more complex and consume higher bias currents than series or shunt PIN diode switches.
• 

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.

In a PIN diode RF switch design, the bias path is connected to the RF path of the switch and DC blocking capacitors are required at the RF port.

• The DC blocking capacitors will degrade the insertion loss performance of the PIN diode switch:
• The DC blocking capacitor degrades the insertion loss performance of the PIN diode switch:
• at low frequencies due to the high pass filter effect of the capacitor.

• At low frequencies, due to the high-pass filtering effect of the capacitor.

• at high frequencies due to SRF (self-resonant frequency), and due to transmission loss through the capacitor.
• At high frequencies, due to the SRF (self-resonant frequency), and due to transmission losses through the capacitor.

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

RF chokes (inductors) are used along the bias path to avoid RF signal leakage.

• 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.

• RF chokes must have high impedance at low frequencies so that the RF signal does not leak through the bias path and cause higher insertion loss. A good rule is that the reactance XL of the inductor at the operating frequency should be at least 10 times higher than the port impedance. If the port impedance is 50Ω XL > 500Ω At the same time, the RF choke should have a high SRF (self-resonant frequency) to achieve a broadband switch design.

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Field Effect Transistor Switch

A field effect transistor (FET) is a semiconductor device that relies on an electric field to control the conductivity of a channel in a semiconductor material.

• The current between the source and drain is controlled by the voltage applied between the gate and source.

• Due to the good control of the drain-source resistance (RDS), FET switching is stable and repeatable.

• Applying a reverse bias voltage between the gate and source causes the depletion region of the junction to expand, thereby "pinching off" the channel between the source and drain and controlling the current propagation through this channel.

• In the OFF state, the conduction channel is depleted (cut off), which causes the FET to present a very high resistance (ROFF). This mechanism provides good isolation at low frequencies.

• A field effect transistor is basically a gate voltage controlled resistor. Insertion loss is largely determined by the channel resistance, and the gate-source capacitance determines the isolation. To increase the isolation (high impedance OFF state), a short (inductive) transmission line is connected between the source and drain to resonate the pinch-off capacitance Coff.

Ideal equivalent circuit for ON and OFF field effect transistors

The inductor L is a short segment of transmission line used to parallel resonant RC combination to enhance the high impedance state. The resistor Rs is the total series resistance when pinched off (undepleted channel resistance plus source and drain contact resistance). High quality (Q) requires small Ron, r, and Coff. A good approximation is:

Scaling the gate width allows a trade-off between isolation and insertion loss. If the grid width is doubled, Ron and Rs are halved, Coff is doubled, and Q is unchanged. Typical Q2 values at 10 GHz and 30 GHz are about 1000 and 100, respectively. In normal operation, the drain has no bias. A negative bias on the gate (relative to the source) pinches the channel off. Zero or positive gate bias turns the channel on.

• The isolation performance of FET switches degrades at higher frequencies due to the effects of drain-source capacitance (CDS).

For example, the CDS reactance XC of a GaAs field effect transistor at 10 GHz is about 320Ω, which can provide a drain-source-drain-source isolation of about 10 dB, which is not sufficient to meet the isolation performance.

A simplified schematic diagram of a single-pole double-throw SPDT switch using a FET is as follows:

To switch RF from the common port to port 2, Q1 and Q4 are reverse biased so that the channel between source and drain is cut off; Q2 and Q3 are forward biased so that a lower channel resistance exists between drain and source.

Q1 and Q3 are used as series devices to switch RF ON and OFF, and for better isolation,

Q3 and Q4 are used to shunt the RF leakage to the OFF port to ground.

• To improve the isolation and linearity of a FET switch, more FETs can be added in series on each arm. Power handling in the OFF state can be increased by "stacking" FETs in series. If done properly, the RF voltage will be divided between the gates. Thus, a double-stacked FET with a 12-volt breakdown can achieve power handling comparable to a PIN diode switch with a 24-volt breakdown.
• For stacked FET switches, ideally the power handling increases with the square of the number of FETs in the stack. A double stack (two FETs in series) can handle four times the power of a single FET. Sufficient isolation is required between adjacent gates to allow voltage to be evenly divided. Resistive gate feed is one way to achieve this.
• In the above-mentioned field effect transistor switch, if a drain-source bypass resistor (few kΩ) is added to each field effect transistor, the overall insertion loss and the linearity of the switch can be improved.

• One disadvantage of stacking FETs in order to improve power handling in the OFF state is that the series resistance (insertion loss) in the ON state is multiplied.

In a FET type switch design, the bias path (V control) is not connected to the RF path of the switch, as in the case of a PIN switch. This provides a simpler DC bias path for the FET switch, eliminating the need for expensive high performance RF chokes and avoiding insertion losses due to the bias path being connected to the RF path, as in the case of a PIN diode switch.

• The ON resistance of a FET is usually higher than that of a PIN diode, resulting in a lower insertion loss performance for a FET switch than for a PIN diode switch.

• As voltage controlled devices, FET switches consume less current than PIN diode switches.

alan000345

What a huge workload. Thanks for sharing and learning.

hellomankind

This is too much work... The switch is hard to find, thanks for sharing, we will learn from it

btty038

hellomankind posted on 2022-4-18 18:46 This is too much work. . . The switch is not easy to find. Thanks for sharing. Let's learn from it.

Many things require repeated reading and communication to understand. RF and microwaves cover a wide range of areas, so we need to continue to explore and learn.