Solid-State Switches for 3-30MHz Antenna Tuner: Alternatives to DPDT Relays?

I'm playing around with an antenna impedance matching or tuner circuit. It consists of inductors and capacitors that are switched into and out of the circuit with relays. See the attached schematic.

Can these relays be replaced by solid-state devices? They have to work at radio frequency, about 3-30MHz. Also, the relays only cost about $2USD per DPDT relay. The advantage of the relays is that they add negligible inductance, capacitance and resistance to the circuit. Also, they're easy for a non-EE (me) to understand.

If they can be replaced, where should I go to learn about designing their replacement?

Thanks so much for your advice and guidance.

-Kevin

The closest you will get to an electromechanical device are MEMS RF switches. They are in wide use and there is a lot of info on the web about them. Most are designed to operate at some GHz, but will usually work down to DC. Because of the application area, they are often in small, difficult (for the amateur)to use packages that would normally require a reflow oven, and have power limits much less than that of the electromechanical variety. Actuation is very low power, unlike a relay, but may need a higher voltage that you would expect since they are electrostatically driven.
Do a search on "RF MEMS switches" and you will find out more about these devices.
Hard to beat electromechanical devices still in most areas, your application is likely to be one of them, since I assume that you are matching an HF transmitter to an antenna, and there is some power involved.
Still worth reading up about them though, an interesting extension of MEMS, which most people encounter in devices like accelerometers. Long live relays!
Cheers,
Richard

@Richard-gabric, thanks so much for this pointer. I've never heard of MEMS switches and was fascinated to learn about them.

You're right, the application is for a amateur radio ('ham') HF transmitter to antenna tuner, so could see up to 150 watts, in my application (1500W is the legal power limit, but I don't have a power amplifier).

I was just convinced that something must have been been developed to replace 60+ (100?) year old relay technology, but it seems nothing beats relays for power handling. And, in this application, even the slowness of actualization isn't an issue.

Thanks, again, for taking the time to write back. Take care.

-Kevin

I once dealt with an HF Transceiver (100W output) that used exactly this technique to tune the antenna matching unit. It used reed relays and was incredibly fast, using only digital logic (no MCUs in those days!). Richard is right, there are no semiconductor devices that would be anything like as good as relays at those power levels. You might be able to use FETs or Bipolar transistors to switch components to ground, but you have the problems of getting devices to work in all 4 quadrants. Best stick with relays