high frequency oscililator design
You can use DDS chip such as AD9854 if you do not care the cost. it is difficult to cover such a broad band with one chip.
The problem is that such wide frequency range simply cannot be covered with a single IC. The 555 is designed as a TIMER, for rather long periods of time, i.e. frequency range from 0.001 Hz to ~50 kHz. Other ICs like XR series can operate from 100 Hz to 10 MHz. Some DDS ICs can run as high as 100 MHz but I doubt that they can generate also ~1 kHz.
You should find ICs suitable for partial ranges and build three or four oscillators.
or would be better off with some sort LC tuned oscillator
Alternately, you can build a LC vco from 500Mhz to 600MHz and mixed with 500Mhz down to 0~100MHz. You can use ADF4360-7 if you do not want to tune. However you have to set the ADF4360's frequency resolution to 1KHz to get the min 1KHz frequency and need isolation between 2 vcos. You can also use a divider( CPLD or others) to generate the low band.
