Go to the below link and download the new driver zip file to desktop and unzip it to the desktop.
In the terminal windows type the below code and press enter.
cd Desktop
Then type the below code and press enter.
cd rtlwifi_new-rock.new_btcoex
then type below command and enter.
make
Type and enter
sudo make install
Type your ubuntu password. then type below command and enter.
sudo modprobe -rv rtl8723be
Then type below line of code in your terminal and press the enter button.
sudo modprobe -v rtl8723be ant_sel=2
then type and enter.
sudo ip link set wlp13s0 up
Then type below command in terminal and enter.It will scan all networks with signal strength.
sudo iw dev wlp13s0 scan
To make the settings permanent,type below command in terminal and press enter.
echo "options rtl8723be ant_sel=2" | sudo tee /etc/modprobe.d/50-rtl8723be.conf
Note: After your OS (Kernel) update, you need to apply these settings again to get strong signal.