Try this:
figure
hp{1} = polarplot([45 160; 0 0]*pi/180, [1 1; 0 0], '--k', 'DisplayName','Induction');
hold on
hp{2} = polarplot([160; 0]*pi/180, [1; 0], '-k', 'DisplayName','Field');
polarplot([40 50; 45 45]*pi/180, [0.8 0.8; 1 1], '-k')
polarplot([155 165; 160 160]*pi/180, [0.8 0.8; 1 1], '-k')
hold off
lgd = legend([hp{1}(1), hp{2}(1)], 'Induction','Field', 'Location','southoutside');
title(lgd, '\itB\rm at 45°')
producing:
.
