We have attempted to compare the behaviour of ionosphere during the deep minimum of solar cycle 23 and its peak. At the same time we have also studied the association of ionospheric behaviour with the solar radiation fluxes. We have selected a Japanese mid latitude station, Okinawa (26.3N, 127.8E) and taken the critical frequency of F2 layer (foF2) derived from ionosonde observations to compare the variability of ionosphere during deep minimum (2007) and peak (2003) of solar cycle 23. We found that the values of foF2 were low during 2007 and extremely high during 2003, showing that ionospheric activity has a direct relationship with the solar activity. We then took three solar proxies namely F10.7 cm, EUV flux (26-34nm) and X-ray flux (1-8Å) and probed the association of foF22003 and foF22007 with these solar proxies during the minimum and peak of cycle. We found that EUV flux and X-ray flux correlate with the foF22003 and foF22007 much better than F10.7cm, during both the phases of the cycle. Therefore we conclude that EUV and X-ray Flux are better solar proxies than F10.7 which have been widely used in previous studies. Moreover, the correlation of both fluxes (EUV and X-ray) is stronger with foF2,2003 than with foF2,2007.