Mainly for the frequency is not the same, millimeter wave and microwave frequency is higher than radio frequency. Broadly speaking, microwave can refer to 300MHz-300GHz signals, and radio frequency refers to 3KHz-300GHz signals, but in engineering they usually denote specific frequency applications.
Radio-frequency integrated circuits (RFics) generally operate at frequencies below 3GHz. Microwave integrated circuits usually work above 3GHz, and millimeter-wave integrated circuits work above 30GHz. Of course, this distinction is not absolute.
In the dielectric circuit, the wavelength of the electromagnetic wave is smaller than that in the vacuum, so as long as the actual transmission wavelength reaches the order of millimeters, it can be called the millimeter wave circuit. Because the frequency is not the same, the operating wavelength varies greatly. Therefore, the size of the circuit is also different, and the size of the RFIC is much larger than the microwave\/millimeter wave circuit.
The higher the frequency, the higher the precision of the integrated circuit. The higher the requirement for machining error.
In addition, because the higher the frequency of electromagnetic waves, the stronger the emissivity, there are more places to pay attention to in the design of high-frequency circuits. I hope my answer is helpful to you, thank you!